National Defence Défense nationale B-GL-361-008/FP-003 ENGINEER FIELD MANUAL VOLUME 8 DEMOLITIONS PART TWO ENGINEERS AND ASSAULT PIONEERS WARNING ALTHOUGH NOT CLASSIFIED, THIS PUBLICATION, OR ANY PART OF IT, MAY BE EXEMPTED FROM DISCLOSURE TO THE PUBLIC UNDER THE ACCESS TO INFORMATION ACT. ALL ELEMENTS OF INFORMATION CONTAINED HEREIN MUST BE CLOSELY SCRUTINIZED TO ASCERTAIN WHETHER OR NOT THE PUBLICATION, OR ANY PART OF IT, MAY BE RELEASED. Issued on authority of the Chief of the Defence Staff
Transcript
N a tio n a lD e f e n c e
D éfensen a tio n a le B-GL-361-008/FP-003
ENGINEER FIELD MANUAL
VOLUME 8
DEMOLITIONS
PART TWO
ENGINEERS AND ASSAULT PIONEERS
WARNING
ALTHOUGH NOT CLASSIFIED, THIS PUBLICATION, ORANY PART OF IT, MAY BE EXEMPTED FROMDISCLOSURE TO THE PUBLIC UNDER THE ACCESS TOINFORMATION ACT. ALL ELEMENTS OF INFORMATIONCONTAINED HEREIN MUST BE CLOSELY SCRUTINIZEDTO ASCERTAIN WHETHER OR NOT THE PUBLICATION,OR ANY PART OF IT, MAY BE RELEASED.
Issued on authority of the Chief of the Defence Staff
2
N a tio n a lD e f e n c e
D éfensen a tio n a le B-GL-361-008/FP-003
ENGINEER FIELD MANUAL
VOLUME 8
DEMOLITIONS
PART TWO
ENGINEERS AND ASSAULT PIONEERS
WARNING
ALTHOUGH NOT CLASSIFIED, THIS PUBLICATION,OR ANY PART OF IT, MAY BE EXEMPTED FROMDISCLOSURE TO THE PUBLIC UNDER THE ACCESSTO INFORMATION ACT. ALL ELEMENTS OFINFORMATION CONTAINED HEREIN MUST BECLOSELY SCRUTINIZED TO ASCERTAIN WHETHEROR NOT THE PUBLICATION, OR ANY PART OF IT,MAY BE RELEASED.
Issued on Authority of the Chief of the Defence Staff
OPI: DAD 8 15 May 98
Demolitions
B-GL-361-008/FP-003 i
FOREWORD
1. B-GL-361-008/FP-003, Engineer Field Manual, Volume 8, Demolitions,Part Two, Engineers and Assault Pioneers, is issued on the authority of the Chiefof the Defence Staff.
2. This publication is effective upon receipt and replacesB-GL-320-009/FP-001 Engineer Field Manual, Volume 9, Demolitions Part Two,(Bilingual) dated 30 September 95.
3. Suggestions for amendments shall be forwarded through normal channels toChief of Land Staff, Attention: Director of Army Doctrine 8 (Protection)
W A R N I N GMISUSE OF WEAPONS, AMMUNITION AND EXPLOSIVES
PURPOSE
1. This warning outlines Canadian Forces policy governing the use or misuse ofweapons, ammunition and explosives.
WEAPONS
2. Firing or attempting to fire locally manufactured weapons, obsolete serviceor foreign weapons, or weapons used for display, ceremonial or trophy purposesin museums, messes, parade grounds, armouries or such like areas is prohibitedexcept when specially authorized by NDHQ.
3. Attention is also drawn to the following references which concern offencesconnected with the use or misuse of weapons:
a. National Defence Act, Section 117;
b. QR&O 103.59;
c. Criminal Code of Canada, Sections 82 to 106; and
d. A-SJ-100-001/AS-000, Security Orders for the Department of NationalDefence, Volume 1, Chapter 30.
AMMUNITION AND EXPLOSIVES
4. Tampering with or use of service and commercial ammunition or explosivesfor other than their designed purpose is prohibited.
5. Except as prescribed in paragraph 6, the modification, breakdown orsectioning of live ammunition for experimental, instructional or any otherpurpose, or manufacture of explosives is forbidden; this prohibition includes:
a. unauthorized interchange of fuses or primers or both;
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b. experiments with blank ammunition to alter the powder charge or tointroduce any other substance into the cartridge case or into the weaponwith the approved cartridge;
c. experiments involving the use of altered propelling charges or burstingcharges with ammunition of any type;
d. the use of any non-service or obsolete ammunition;
e. the use of foreign ammunition other than that received through normalsupply channels or supplied in accordance with NATO Standardizationagreements;
f. the manufacture and use of locally fabricated explosive trainingdevices, battle simulators, saluting charges, etc;
g. any alteration to design of ammunition or explosive devices;
h. deviations from authorized drills for use of ammunition or explosivedevices; and
j. rendering live ammunition inert for use as museum or instructionalitems.
6. The prohibition in paragraph 5 does not apply to:
a. authorized experiments, modifications, etc, carried out by experimental,research, proof or inspection establishments;
b authorized breakdown, modification, repairs, proof-testing, etc, carriedout as normal functions of a Canadian Forces Ammunition Depot orbase ammunition facility;
c. personnel employed at Canadian Forces School of Electrical andMechanical Engineering as instructors or trainees under supervision,when breaking down is carried out as part of a course training standardand in accordance with an approved course training plan;
d. the use, in its designed role, of commercial pattern ammunitionobtained by local purchase as specified in CFP 137 or as authorized byNDHQ in accordance with CFAO 36-19;
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iv B-GL-361-008/FP-003
e. the use, in its designed role, of commercial pattern ammunition whichis taken into service and catalogued;
f. hand-loading small arms ammunition in accordance with CFAO 50-18;or
g. other cases, when specifically authorized by NDHQ
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TABLE OF CONTENTSFOREWORD ....................................................................................................... IW A R N I N G MISUSE OF WEAPONS, AMMUNITION AND
SECTION 1 DEMOLITIONS IN THE DIFFERENT PHASES OF WAR.......9SECTION 2 RECONNAISSANCE.................................................................11SECTION 3 CONTROL OF DEMOLITIONS ...............................................16SECTION 4 RESERVED DEMOLITIONS....................................................22ANNEX A - OBSTACLE RECCE REPORT ................................................29ANNEX B - BRIDGE RECCE REPORT .......................................................31ANNEX C - OBSTACLE TASK TABLE.......................................................34ANNEX D - OBSTACLE FOLDER-GERMANY CF 765 (STANAG 2123) 37ANNEX E - DEMOLITION ORDER (DND 913)..........................................39
CHAPTER 3 SERVICE DEMOLITION STORES AND EQUIPMENT ......41SECTION 1 GENERAL..................................................................................41SECTION 2 SHAPED CHARGES .................................................................45SECTION 3 SPECIFIC TASK MILITARY EXPLOSIVES...........................57SECTION 4 ELECTRICAL ACCESSORIES AND EQUIPMENT ..............63SECTION 5 MISCELLANEOUS EQUIPMENT ...........................................70ANNEX A - TYPES OF EXPLOSIVES.........................................................76ANNEX B - MILITARY EXPLOSIVES LOGISTICAL DATA....................79ANNEX C - COMMERCIAL EXPLOSIVES AND ACCESSORIES ...........82ANNEX D - IMPROVISED CHARGES ........................................................91APPENDIX 1 - AMMONIUM NITRATE AND FUEL OIL (ANFO) ...........96
CHAPTER 4 ELECTRICAL PROCEDURES...............................................103SECTION 1 SAFETY ...................................................................................103SECTION 2 FIRING CIRCUITS..................................................................108SECTION 3 ELECTRICAL INITIATION ...................................................114ANNEX A - INSTRUCTIONAL, TRAINING AND EXERCISE SAFETY
DISTANCES .............................................................................125ANNEX B - OPERATIONAL SAFETY DISTANCES................................127
SECTION 6 DENIAL OPERATIONS.........................................................172ANNEX A - METHODS OF ATTACK SIMPLY SUPPORTED BRIDGES179ANNEX B - METHODS OF ATTACK CONTINUOUS BRIDGES ...........185ANNEX C - PRIORITIES OF DENIAL OPERATIONS .............................193
CHARGE END CROSS SECTION FOR BLOCKS OF C4 .....260ANNEX B CUTTING CHARGE REQUIRED FOR ROUND STEEL BAR
AND STEEL WIRE ROPE IN BLOCKS OF C4......................262ANNEX C CUTTING CHARGE RECTANGULAR TIMBER, \
CHARGE END CROSS SECTION FOR BLOCKS OF C4 .....264ANNEX D CUTTING CHARGE FOR ROUND TIMBER
IN BLOCKS OF C4 ..................................................................265ANNEX E CUTTING CHARGE FOR MASONRY AND UNREINFORCED
CONCRETE, CHARGE END CROSS SECTION FORBLOCKS OF C4........................................................................267
ANNEX F CUTTING CHARGES FOR REINFORCED CONCRETEBEAMS AND SLABS UP TO 22.5 CM,CHARGE END CROSS SECTION ..........................................269
ANNEX G CONCRETE STRIPPING CHARGE, PER METRE RUN......271ANNEX H CONCRETE BREACHING CHARGE.....................................273ANNEX I PIER FOOTING CHARGE IN BLOCKS OF C4 .....................275ANNEX J GENERAL INFORMATION ON MAKING HOLES AND
CUTTING CHANNELS IN PIERS, ABUTMENTS, ETC......335ANNEX K BOREHOLE CHARGES IN TIMBER (C4).............................337ANNEX L CRATERING AND DITCHING CHARGES IN BLOCKS OF C4338ANNEX M BURIED CHARGES BEHIND ABUTMENTS -
SUMMARY OF CHARGES REQUIRED BASED ONDELIBERATE FORMULA ......................................................281
CHAPTER 7 CRATERING PROCEDURES AND RELATED SAFETYPRECAUTIONS ......................................................................283
CHAPTER 8 DEMOLITIONS IN PARTICULAR ENVIRONMENTS.....290SECTION 1 DEMOLITIONS UNDER WATER ........................................290SECTION 2 DEMOLITIONS IN SUB - FREEZING CONDITIONS........303
6 .......................................................................................................33Fig 2C-1 Obstacle Task Table (CF 682) front.....................................................34Fig 2C-1 Obstacle Task Table (CF 682) back.....................................................35Fig 2E-1 Demolition Order (DND 913) front .....................................................39Fig 2E-1 Demolition Order (DND 913) back......................................................40Fig 3-1-1 NATO interchangeability symbol ........................................................42Fig 3-1-2 Summary of compatible demolition accessories .................................43Fig 3-2-1 Shaped charge and target.....................................................................45Fig 3-2-2 Shaped charge jet formation ................................................................46Fig 3-2-3 Shaped charge penetration...................................................................46Fig 3-2-4 Types of shaped charges......................................................................47Fig 3-2-5 Conical shaped charge effectiveness ...................................................47Fig 3-2-6 Methods of arming (with and without M1A4, adapter).......................48Fig 3-2-7 Charge demolition, 15 lb, M2A4.........................................................49Fig 3-2-8 Charge Demolition, 40 lb, M3A1........................................................49Fig 3-2-9 Adapter, priming, M1A4 .....................................................................51Fig 3-2-10 Use of M1A4 adapter ........................................................................51Fig 3-2-11 Charge Demolition, No 14, 11 lb Mk1(Hayrick)...............................52Fig 3-2-12 Methods of use-Charge Demolition, No, 14 (Hayrick) .....................53Fig 3-2-13 Charge Demolition, No 14 (Hayrick), configuration.........................53Fig 3-2-14 Charge Demolition, No 14 (Hayrick), configuration.........................53Fig 3-2-15 Container Demolition, C126..............................................................55Fig 3-2-17 Container Demolition, C126 and liner C1, schematic .......................55Fig 3-2-16 Liner steel, C1 ...................................................................................55Fig 3-3-1 Container, Trigran ...............................................................................57Fig 3-3-2 Arming Detasheet................................................................................58Fig 3-3-3 Uli knot................................................................................................58Fig 3-3-4 Charge Assembly, Demolition, MK 138 (satchel charge) ...................59
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Fig 3-3-5 Satchel charge explosive lead...............................................................59Fig 3-3-6 Explosive training charge C2/C2A1.....................................................60Fig 3-4-1 Typical electric detonator ....................................................................63Fig 3-4-2 Igniter, time blasting fuse, electric, C2 (igniter electric) .....................64Fig 3-4-3 Blasting machine, ZEB/C100S............................................................65Fig 3-4-4 Ohmmeter, ZEB/WO...........................................................................67Fig 3-5-1 Camouflet Set, MK 1...........................................................................70Fig 3-5-2 Demolition ladder C2 ..........................................................................71Fig 3-5-3 Safety belt............................................................................................72Fig 3-5-4 AEV with Ladder ................................................................................73Fig 3-5-5 Typical Bolt Gun .................................................................................73Fig 3-5-6 Typical Fasteners.................................................................................73Fig 3-5-7 BERFS in transit case..........................................................................75Fig 3-5-8 BERFS transmitter...............................................................................75Fig 3-5-9 BERFS receiver ...................................................................................75Fig 3B-1 Military plastic explosives ...................................................................80Fig 3B-2 Shaped charges.....................................................................................80Fig 3B-3 Miscellaneous military explosives .......................................................81Fig 3B-4 Military explosive accessories .............................................................81Fig 3C-1 Explosive Density ................................................................................83Fig 3D-1 Antitank mine prepared as an improvised charge ................................91Fig 3D-2 Arming bombs as demolition charges..................................................92Fig 3D-3 Improvised Bangalore torpedo (1.8 m iron pickets) ............................92Fig 3D-4 Improvised antipersonnel pipe charge .................................................93Fig 3D-5 Improvised directional mine ................................................................93Fig 3D-6 Improvised shaped charge....................................................................94Fig 3D-7 Platter charge .......................................................................................95Fig 3D1-1 Ratio of PAN to fuel oil according to SG ..........................................98Fig 3D1-2 Volume Measurement ........................................................................98Fig 3D1-3 Weight Measurement (Using PAN with a SG of 0.8 gm/cm3)...........99Fig 3D1-4 Timber mixing trough ......................................................................100Fig 4-1-1 Joints in demolition cable ..................................................................105Fig 4-1-2 Safety distances for field radio and radar equipment.........................106Fig 4-1-3 Safety Distances from civilian radio, television or radar transmitters
.......................................................................................................107Fig 4-2-1 Trunkline ...........................................................................................108Fig 4-2-2 Ring main ..........................................................................................109Fig 4-2-3 Simple firing circuit...........................................................................110Fig 4-2-4 Maximum firing circuit .....................................................................110Fig 4-3-2 Closed circuit signal ..........................................................................115Fig 4-3-1 Open circuit signal..............................................................................115Fig 4-3-3 Shunt and ground signal ....................................................................115
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x B-GL-361-008/FP-003
Fig 4-3-4 Connecting an electric detonator to demolition cable in a singledetonator firing circuit ..................................................................118
Fig 4-3-5 Resistance of Copper Wire................................................................120Fig 4-3-6 Connecting lead wires in a multi-detonator firing circuit ..................121Fig 4-3-7 Connecting detonators to demolition cable in multi-detonator firing
circuit .............................................................................................122Fig 4A-1 Instructional, training and exercise safety distances ..........................126Fig 4B-1 Operational safety distances...............................................................128Fig 5-2-1 Demolition of tunnel in hard ground or rock......................................137Fig 5-3-1 Use of debris to delay rebridging. ......................................................139Fig 5-3-2 No collapse mechanism.....................................................................140Fig 5-3-3 Jammed collapse mechanism.............................................................141Fig 5-3-4 Types of collapse mechanism............................................................141Fig 5-3-5 Simply supported bridge spans..........................................................142Fig 5-3-6 Identification of simply supported and continuous spans..................143Fig 5-3-7 Simply supported categorization chart ..............................................144Fig 5-3-8 Steel beam bridge typical cross-sections ............................................144Fig 5-3-9 Steel truss bridges..............................................................................145Fig 5-3-10 Mid-span cross-sections concrete bridges .......................................145Fig 5-3-11 Simply supported, bowstring, normal..............................................146Fig 5-3-12 Simply supported, bowstring, reinforced.........................................146Fig 5-3-13 Type of arch bridge ..........................................................................146Fig 5-3-14 Measurements of simply supported spans .......................................147Fig 5-3-15 Lines of attack .................................................................................148Fig 5-3-16 Required end clearance (ER) at supports for mid-span bottom attack
.......................................................................................................149Fig 5-3-17 Minimum length of section to be removed (LC) for a mid span attack
.......................................................................................................152Fig 5-3-18 Continuous bridge categorization chart ...........................................154Fig 5-3-19 Cantilever bridge .............................................................................154Fig 5-3-20 Cantilever and suspended span bridges ...........................................155Fig 5-3-21 Continuous, steel beam, without short side span .............................155Fig 5-3-22 Continuous, steel beam, with short side span ..................................155Fig 5-3-23 Continuous, steel truss.....................................................................155Fig 5-3-24 Typical portal bridge .......................................................................156Fig 5-3-25 Typical arch bridge shapes ...............................................................156Fig 5-3-26 Continuous, concrete arch, solid spandrel pinned footing ...............156Fig 5-3-27 Continuous, concrete arch, open spandrel, pinned footing .............156Fig 5-3-28 Continuous masonry arch ................................................................157Fig 5-3-29 Measurements of continuous bridges ..............................................157Fig 5-3-30 Minimum length of section to be removed for arch and pinned
Fig 5-3-31 Swing span truss bridge...................................................................161Fig 5-3-32 Double leaf bascule bridge ..............................................................161Fig 5-3-34 Vertical lift bridge ............................................................................162Fig 5-5-1 Demolition shafts...............................................................................167Fig 5-5-2 Beam post obstacle ............................................................................169Fig 5-5-3 Falling block obstacle........................................................................170Fig 5-6-1 Demolition of dams ...........................................................................177Fig 6-1-1. Explosive charge index......................................................................197Fig 6-1-2. List of formula notations. ..................................................................199Fig 6-1-3. Explosive Factors. ............................................................................200Fig 6-2-1 Calculations - cutting charge for steel girder....................................203Fig 6-2-2 Charge placement for steel girder........................................................204Fig 6-2-3. Charge Placement for Steel ...............................................................205Rail. .......................................................................................................205Fig 6-2-4 Charge Placement for a Steel Wire Rope of ......................................207Circumference Greater than 22.0 cm...................................................................207Fig 6-2-5. Charge Placement for Steel Chains. ..................................................207Fig 6-2-6 Saddle Charge....................................................................................208Fig 6-2-7. Charge placement for timber piles underwater........................212Fig 6-2-8. Charge placement for tree.................................................................212felling. .......................................................................................................212Fig 6-2-9. Line of Cut.........................................................................................216Fig 6-2-10. Effect of a concrete stripping charge ..............................................219Fig 6-2-11. Section of bridge at midspan showing placement of .......................221concrete stripping charges. ..................................................................................221Fig 6-3-1. Breaching charges for reinforced concrete obstacles and.................224walls. .......................................................................................................224Fig 6-3-3 Dragon's teeth prepared .....................................................................226for destruction .....................................................................................................226Fig 6-3-4 Breaching walls. ................................................................................226Fig 6-3-5 Breaching reinforced concrete piers. .................................................227Fig 6-3-4 Ear-muff charge.................................................................................228Fig 6-4-1 Example masonry pier ........................................................................230Fig 6-4-2 Charge placement for ........................................................................231pier on slope. .......................................................................................................231Fig 6-4-3. Charge placement for pier on ............................................................232level ground .......................................................................................................232Fig 6-4-4 Charge placement for pier .................................................................232standing in water .................................................................................................232Fig 6-5-1. Borehole Charge Placement ..............................................................236Fig 6-5-2. Volume of explosive per borehole.....................................................238Fig 6-5-3 Sketch of borehole layout in concrete (end view at right) .................238
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Fig 6-5-4 Borehole layout in timber ..................................................................241Fig 6-6-1 Calculation table for craters...............................................................243Fig 6-6-2 Ditching with explosives ...................................................................246Fig 6-6-3. Continuous mined charges - size of charge. ......................................247Fig 6-6-4 Example for continuous mined charges and......................................248tamping in a culvert.............................................................................................248Fig 6-6-5 Mined charges for blowing abutments and........................................252retaining walls. ....................................................................................................252Fig 6-6-6 Charge placement - continuous and small mined ..............................252charges behind abutments. ..................................................................................252Fig 6-6-7. Charge placement ..............................................................................254for stump blasting................................................................................................254Fig 6-6-8. Charge Size for Boulder Removal. ....................................................254Fig 6-6-9. Charge placement for ........................................................................255boulder blasting. ..................................................................................................255Fig 6-7-1 Values of K for concussion charges. .................................................258Fig 6A-1 Cutting charge for rectangular steel charge end cross section ...........260for blocks of C4...................................................................................................260Fig 6B-1 Cutting charge required for round steel bar and steel wire.................263rope in blocks of C4 ............................................................................................263Fig 6C-1 Cutting charge for rectangular timber charge end cross section.........264for blocks of C4...................................................................................................264Fig 6D-1 Cutting charge for round timber in blocks of C4 ...............................265Fig 6E-1 Cutting charge for masonry and unreinforced concrete charge end cross
section for blocks of C4 .................................................................268Fig 6F-1 Cutting charges for reinforced concrete beams and slabs up to..........27022.5 cm charge end cross section ........................................................................270Fig 6G-1 Concrete stripping charge per meter run............................................271Fig 6H-1 Concrete breaching charge in blocks of C4 per meter of material .....273Fig 6I-1 Pier footing charges in Blocks of C4...................................................275Fig 6J-1 General information on making holes and cutting channels in piers,
abutments, etc. ...............................................................................336Fig 6K-1 Borehole charges in timber (C4)........................................................337Fig 6L-1 Cratering and ditching charges in blocks of C4..................................338Fig 6M-1 Buried charges behind abutments - summary of charges required based
on deliberate formula .....................................................................281Fig 7-1 Camouflet procedure.............................................................................288Fig 8-1-1 Blasting a channel through a sand bar using Bangalore torpedoes.....296Fig 8-1-2 Typical shaped charge container .......................................................298Fig 8-1-3 Initiating charges underwater ............................................................300Fig 8-1-4 Underwater Dual Non-Electric Initiation Set ....................................301Fig 8-1-5 Underwater dual electric initiation ....................................................301
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Fig 8-1-6 Dual initiation secured to detonating cord.........................................302Fig 8-2-1 Sub-surface ice demolition charge placement. ..................................304Fig 8-2-2 Hasty Sub-Surface Ice Charge Calculation Table .............................305Fig 8-2-3 Surface Charge Hasty Calculation.....................................................306Fig 9-1 Battle simulation safety distances .........................................................309Fig 9-2 BERFS layout .......................................................................................310Fig 9-3 Examples of ripple boards ....................................................................311Fig 9-4 Safety Fuze Lengths..............................................................................312Fig 9-5 Minimum distances between battle simulations ...................................312Fig 9-6 Small arms circuit layout ......................................................................314Fig 9-7 Mortar and artillery fire circuit layout ..................................................315Fig 9-8 Linear barrage circuit layout.................................................................316Fig 9-9 Smoke pot No 24 MK 2........................................................................317Fig 9-10 Railway fusee......................................................................................318Fig 9-11 Grenade, hand, smoke, HC, C1 Series .................................................319Fig 9-12 Simple small nuclear simulator...........................................................320Fig 9-13 Napalm layout.....................................................................................321
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B-GL-361-008/FP-003 1
CHAPTER 1INTRODUCTION
GENERAL
1-1. Demolition is defined as the destruction of structures, facilities, ormateriel by the use of fire, water, explosives, mechanical or other destructivemeans. Explosive demolitions are used for both destructive and constructivepurposes, including:
a. clearing obstacles or obstructions and destroying fortifications;
b. impeding the opposing force by destroying bridges, cratering roads andairfields, and creating other obstacles such as blowdown in defiles orstructures in built-up areas;
c. aiding in the preparation of field defences such as two-man battletrenches, artillery gun positions, hull-down positions for armour, andcommand posts;
d. denying areas, facilities, equipment and supplies to the opposing force;
e. preparing sites for general construction work; and
f. quarry operations.
RESPONSIBILITIES
1-2. Simple demolition tasks that all arms soldiers shall be capable ofcompleting are described in B-GL-320-009/FP-001, Engineer Field Manual,Volume 9, Demolitions, Part One, All Arms, and include:
a. using the Bangalore torpedo;
b. using explosives to assist digging in;
c. destroying vehicles and equipment; and
d. destroying user blinds and misfired ammunition.
1-3. Engineers are responsible for executing the more technical demolitiontasks requiring special skills, training and equipment; these tasks are usuallyauthorized and controlled at the formation level and support the formation
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commanders plan. Assault Pioneers are responsible for executing close supportdemolition tasks such as minor demolitions, craters, abatis, and clearance ofobstacles which support their unit commanders plan. In addition, engineers areresponsible for providing basic demolition training and advice to the remainder ofthe Canadian Forces.
AIM
1-4. The aim of this manual is to provide a reference for all ranks of fieldengineers and assault pioneers on demolition tasks not covered inB-GL-320-009/FP-001, Engineer Field Manual, Volume 9, Demolitions, PartOne, All Arms. It contains sufficient detail to be used both as a reference forinstructors and as a field manual. This manual shall be used in conjunction withB-GL-320-009/FP-001, which explains the theory of explosives and basicdemolition safety.
SCOPE
1-5. This manual covers the following aspects of demolitions:
a. operational employment of demolitions;
b. demolition stores and equipment;
c. electric initiation and safety procedures;
d. typical demolition tasks;
e. charge calculation and placement;
f. denial operations; and
g. ice and underwater demolitions.
REFERENCES
1-6. References and standardization agreements used for the writing of thispublication are listed at Annex A to this chapter. Other manuals that containaspects of demolitions that can be used in conjunction with this manual are alsolisted at Annex A to this chapter.
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UNITS OF MEASUREMENT
1-7. This manual uses metric (SI) units throughout. Conversion tables formetric to imperial units are at Annex B to this chapter.
TERMINOLOGY
1-8. A glossary of demolition terms used in provided at the end of thismanual.
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ANNEX AREFERENCES AND STANDARDIZATION AGREEMENTS
1A-1. The following publications are related to and should be used inconjunction with this publication:
a. B-OL-303-002/FP-001, Staff Manual, Volume 2, Operational StaffProcedures,
h. STANAG 2989 Transfer of Barriers, Edition 1, Amendment 3; and
j. QAP 64 Demolitions, Explosives and Accessories Catalogue, May1991.
1A-3. The following foreign publications have been used as a reference forthis manual:
a. Military Engineering Volume II, Field Engineering, Pamphlet No. 4,Demolition, 1988; and
b. FM 5-250 Explosives and Demolitions, June 1992.
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1A-4. The following civilian publications have been used as a reference forthis manual:
a. C-09-011-00/AB-000 C.I.L. Blaster's Handbook, 6th Edition, 1984; and
b. Dupont Blaster's Handbook, 16th Edition, 1977.
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ANNEX BINTERNATIONAL SYSTEM OF UNITS (METRIC) IMPERIAL
CONVERSION TABLES
Ser Unit Mile Kilo-metre(km)
Metre(m)
Yard(yd)
Foot(ft)
Inch(in)
Milli-metre(mm)
(a) (b) (c) (d) (e) (f) (g) (h) (i)12
34567
MileKilo-metreMetreYardFootInchMilli-metre
10.621
---------------
1.6091
---------------
16091000
10.9140.305------
17601094
1.09410.333------
52803281
3.281310.083---
------
39.4361210.039
------
1000914.430525.41
Fig 1B-1 Length equivalents
Ser Unit Squaremile
Squarekilometre
(km2)
Squaremetre(m2)
Squareyard(yd2)
Acre Hectare
(a) (b) (c) (d) (e) (f) (g) (h)1
23456
Square mileSquare kmSquare mSquare ydAcreHectare
1
0.4------------
2.6
1------------
---
---10.836404710,000
---
---1.1961484011,960
640
247------12.47
259
100------0.4051
Fig 1B-2 Area equivalents
Ser Unit Cubic inch Cubic foot Cubic yard Cubic metre(a) (b) (c) (d) (e) (f)1234
Cubic inchCubic footCubic yardCubic metre
11728------
---12735.32
---0.0411.31
---0.0280.4651
Fig 1B-3 Volume equivalents
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Ser Unit Metric tonne Short ton Kilogram Pound(a) (b) (c) (d) (e) (g)1234
Metric tonneShort tonKilogramPound
10.984------
1.0161------
100098410.454
220520002.2051
Fig 1B-4 Weight equivalents
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CHAPTER 2OPERATIONAL DEMOLITIONS
SECTION 1DEMOLITIONS IN THE DIFFERENT PHASES OF WAR
GENERAL
2-1-1. Fire and movement are decisive factors in all operations and obstaclesare a decisive factor in movement. The barrier plan must be closely coordinatedwith all other tactical plans. Engineers are responsible for preparing fordemolition, whereas formation commanders and staff are responsible, withengineer advice, for planning and for ordering demolitions.
2-1-2. The availablity of engineers, and time to prepare the many obstacles ina barrier plan are often limited. It is essential that formation commandersestablish a strict priority for the targets chosen. The commander states the degreeof damage or delay to be achieved for each target based upon the threat. Thispriority list is created so engineer effort is concentrated on the critical obstaclesand the lower priority targets can be executed if more time, engineers and materialbecome available.
TYPES OF DEMOLITION TARGETS
2-1-3. To prepare and maintain demolitions until the last possible moment isnot effective nor desirable. Demolitions are therefore classified as preliminary orreserved. Ideally, all demolition targets should be preliminary. However, theneed to maintain routes for patrols or withdrawing forces, and to protect facilitiesof strategic importance such as refineries or power stations, requires that certaintargets be designated as reserved targets. The designation of a reserved target isdone by the Authorized Commander, who is the commander empowered to orderthe emplacing of the obstacles.
DEMOLITIONS IN DEFENSIVE OPERATIONS
2-1-4. General. Although there are many uses of demolitions in war, theiremployment is likely to be of greater importance during the defensive battle.Demolitions impede the opposing force's mobility and force them toconcentrate sufficiently to provide a worthwhile target. 2-1-5. Covering Force Battle. Covering forces are deployed forward of themain defensive area to protect the deployment of friendly forces, to delay theenemy, and to identify the main axis of their advance. Demolition obstacles arecreated to impede an enemy's mobility as it advances. Rather than concentrating
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obstacles in one particular area, engineers must develop them through the depth ofthe covering force area. Route denial is an integral part of delaying andwithdrawal operations. Good control is necessary to ensure that parties progressat roughly the same rate and that a route remains clear for withdrawing forces.
a. Delaying Operations. Demolition tasks in the delay are designed toassist a force to gain time by slowing the enemy advance. If necessary,the delaying force trades terrain for time and in principle, avoidsbecoming decisively engaged. Obstacles are constructed or improvedto delay or disrupt the opposing force by the destruction or obstructionof routes and defiles.
b. Withdrawal Operations. Demolition tasks in the withdrawal aredesigned to assist a force to disengage or break contact from anopposing force. Demolitions deny facilities and terrain to the opposingforce including the destruction of roads, airfields, crossing sites, waterand petroleum installations, supply dumps, etc. A strategic withdrawalmay require the implementation of a scorched earth policy.
2-1-6. Main Defensive Phase. The main defensive phase is preferably basedon a natural obstacle such as a river or escarpment and reinforced by artificialobstacles. Obstacles sited in depth are desirable but not always possible.Demolitions are used mainly for the destruction of river bridges and routesthrough a barrier. Since the covering force must eventually withdraw through thebarrier, the preparation of the barrier shall be carefully coordinated with theirmovement plan and some of the demolitions will be designated as reserved.
2-1-7 Countermove Phase. In the countermove phase, the tacticalcommander may reinforce, block, or counter-attack to contain and destroy theenemy. Counter-mobility obstacles will be required to assist in blocking opposingforce penetrations and for flank protection. Demolitions may be used tostrengthen the barriers along the enemy approaches and to recreate obstacles aftersuccessful breaching by the enemy.
2-1-8 Planning. The actual execution of the demolitions, occurs during thetransition between the covering force phase and the main defensive phase. Thebarrier plan is based on zones normally specified on a geographical or area basisto support the tactical commander's plan. Barrier planning is covered in detail inB-GL-319-001/FT-001, Engineers in Battle.
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DEMOLITIONS IN OFFENSIVE OPERATIONS
2-1-9. General. Although the main employment of demolitions is defensive,they can be used during offensive operations. The amount of explosives andaccessories that can be used is generally limited by the carrying capacity of thesoldier or vehicles, or in some cases aircraft. Demolition tasks in the offence arelikely to be minor in nature, or at least technically simple and are mainly used to:
a. clear or breach obstacles in the advance;
b. harass the enemy during a pursuit; and
c. protect one or both flanks.
2-1-10. Clearing or Breaching of Obstacles. Obstacles impede the mobilityof an advancing or attacking force. Procedures to cross or breach them requiresteam work and thorough rehearsals. Engineer reconnaissance parties shall movewith the lead elements of an advancing force, while engineer resources move closebehind to deal with obstacles as they are encountered. Engineers may requireclose protection by an infantry/armoured force. Obstacles that will have to becleared, dismantled or filled during the advance or attack include minefields,abatis, roadblocks, craters, concrete or log post obstacles, fortifications, andbuilding debris in urban areas.
2-1-11. Harassing the Enemy during a Pursuit. The use of demolitions inthe pursuit are likely to be aimed at defiles on enemy withdrawal routes. They arecompleted by infiltration, deep and rapid penetration, helicopter assault, or byremotely delivered mines.
2-1-12. Flank Protection. Engineer demolition tasks in support of flankprotection during an advance include the preparation of hasty obstacles for localprotection and route denial tasks. Route denial tasks involve engineer partiesmoving down several routes and preparing obstacles on each route.
SECTION 2RECONNAISSANCE
GENERAL
2-2-1. Demolition planning follows the same planning sequence as for otherengineer tasks. Junior engineer officers and NCOs play an important part in theplanning sequence. Detailed reconnaissance (recce) reports enable engineercommanders to make sound estimates of time, labour and resources to advise
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commanders and staffs during the preparation of tactical plans and the barrierplan.
2-2-2. The purpose of a demolition recce is to provide information on thetarget, and determine the:
a. method of demolition;
b. time and labour required;
c. quantity of mines and explosives required; and
d. equipment and other stores required.
RECONNAISSANCE ORDERS
2-2-3. A detailed recce is generally undertaken by a junior engineer officer orsenior NCO. Before starting, there must be clear instructions which assists indetermining the best method of destroying the target and estimating the explosivesrequired. These instructions shall cover the following points:
a. where and when the report is required;
b. identification, location, and nature of the target;
c. tactical objective of the obstacle (delay that must be imposed, andwhether it is intended to impede tracked and/or wheeled vehicles);
d. whether it is a preliminary or reserved demolition;
e. when the demolition is to be ready to State1 (SAFE), and length of timeallowed for changing the state of readiness to State 2 (ARMED);
f. if hasty or deliberate calculations are to be used;
g. any restrictions or conditions for closing the route;
h. type of mines, explosives, equipment and labour available; and
j. availability of other engineer intelligence (such as air photos).
ORGANIZING THE RECONNAISSANCE
2-2-4. Generally, the composition of a demolition recce party will be kept to aminimum in personnel and equipment. When reconnoitering assault targets close
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to the opposing force, personal protection takes the form of concealment andstealth, and may include a protection party.
2-2-5. The composition and equipment of the party must be suited to the kindof information to be obtained. In a simple recce, when the measurements to betaken are few and easy to obtain, an officer or senior NCO with one assistantshould suffice. Complicated targets, involving numerous sets of measurements,which may require the use of demolition ladders and other aids, require largerrecce parties. Specialists or advisors, such as a technician able to recogniseapparatus in a power station, or an expert in concrete reinforcement, may beincluded as required. The commander of a large recce party should be free toreconnoitre the area in general (perhaps to decide on the location of firing points)while the remainder conduct the actual target reconnaissance according to hisinstructions.
2-2-6. The following stores and equipment will be useful to a demolition recceparty:
a. two metre measuring rods and flexible steel tapes x 2 each;
b. 30 metre tape x 1;
c. leadline (for depth of water) x 1;
d. recce boat x 1;
e demolition ladder (lengths) and demolition safety belt x 1 each;
f. chisel x 1;
g. large hammer x 1;
h. cordage and twine;
j. recce proforma;
k. Engineer and Assault Pioneer Field Pocket Book;
m. camera and tape recorder (if available) x 1 each; and
n. chalk, spray paint or paint and brush.
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COMPLETING THE RECONNAISSANCE
2-2-7. Tasks. The main tasks are:
a. decide on the general method of attack, including type of charges to beused and where to put them;
b. take general measurements to describe the target;
c. take detailed measurements at the points of attack so that charges canbe calculated;
d. calculate explosives, time, labour, and other requirements;
e. complete the demolition recce proforma;
f. select the firing point(s). For a reserved demolition this will have to bedone in consultation with the Demolition Guard Commander; and
g. draw a sketch of the target and site.
2-2-8. Recce Proforma. As much of the demolition recce proforma aspossible shall be completed with the target in view. If this is not possible, roughnotes can be used later, with possibly a tape-recorded target description andphotograph.
2-2-9. Method of Demolition. Before deciding on the method of attack, theobjective of the demolition must be considered. The recce officer or NCO willdecide the method of demolition which best ensures success. Points which shallbe considered are:
a. progressive preparation sequence;
b. protection of long standing demolitions, or demolitions in areas ofheavy traffic; and
c. resources available (explosives, mines, equipment, and time).
2-2-10. Demolition Calculations. Demolition calculations are discussed inChapter 6.
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RECONNAISSANCE REPORTS
2-2-11. Demolition Recce Reports. Demolition recce reports are used torecord the information collected. Their use saves time and ensures all thenecessary information is collected. The obstacle recce report (E120B) at Annex Ais used for all demolition task reconnaissances except bridges. The bridgedemolition recce proforma (E121B) is at Annex B to this chapter.
2-2-12. Obstacle Task Table (CF 682). Information from a demolition reccereport can be incorporated with other obstacle planning information on a CF 682,Obstacle Task Table, which serves as a planning tool for work scheduling andresource management. An Obstacle Task Table appears at Annex C.
2-2-13. Obstacle Folder. In cases of a long standing threat, demolitions maybe planned during peacetime and some preparation may be completed. These areknown as peacetime prepared obstacles. In this case, detailed information oneach target including the method of attack, prestocked stores and explosives, andother information may be gathered in an Obstacle Folder, which is described inAnnex D to this chapter. This obstacle folder is standardized throughout NATOin STANAG 2123.
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SECTION 3CONTROL OF DEMOLITIONS
GENERAL
2-3-1. Unlike other obstacles which become progressively more effective aswork proceeds, demolitions are not effective until the charge is fired. The enemymay conduct harassing attacks to prevent the execution of the demolition or forcea premature firing to hinder the withdrawal of friendly troops. The control ofdemolitions is therefore very important.
DEMOLITION ORDER
2-3-2. Instructions for the execution of a demolition target are issued bywritten or verbal orders prior to an operation commencing, or by the DemolitionOrder DND 913 (Annex E). Instructions for the execution of a demolition taskmust include:
a. identification, type and location of the target;
b. tactical objective of the demolition (gap required);
c. reserved or preliminary;
d. technical details;
e. restrictions on firing and emergency firing instructions;
f. mines, explosives, equipment and manpower assigned to the task;
g. by when the demolition is to be executed or prepared to State 1(SAFE);
h. restrictions on closing the route to traffic;
j. reports and returns required; and
k. security.
2-3-3. The Demolition Order is based on NATO STANAG 2017. It shall beused for a reserved demolition and may be used for a preliminary demolition.Instructions for its use are printed on the form. Distribution is as follows:
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a. Demolition Guard Commander - Copy 1(White);
b. Demolition Firing Party Commander - Copy 2(Green);
c. Authorized Commander - Copy 3(Canary); and
d. spares - Copy 4(Pink) and Copy 5(Goldenrod).
2-3-4. Codes used with the Demolition Order may consist of a word, anumber, a series of numbers, or a series of letters. The Canadian procedure is touse a word.
STATES OF READINESS
2-3-5. State 1 (SAFE). Notwithstanding the NATO definitions contained inthe glossary, the Canadian context of State 1 (SAFE) is as follows:
a. the charges are placed and secured;
b. the vertical and horizontal ring mains are installed but not connectedtogether. The charges are connected to the vertical ring mains. Thismay reduce the possibility of both the vertical and horizontal ring mainsdetonating at the same time due to artillery or air strikes or sabotage.There may be cases when vertical and horizontal ring mains must beconnected at State 1 due to the size of the target, time available tochange states, or the inaccessibility of portions of the ring main; and
c. detonators and initiation sets are not connected or installed.
2-3-6. State 2 (ARMED). On changing to State 2 (ARMED), the Canadiancontext is:
a. the vertical and horizontal ring mains are connected together; and
b. the detonators and initiation sets are connected.
2-3-7. Changing to State 2 (ARMED) must be accomplished as quickly aspossible. This change shall be rehearsed during the day, at night, and during allweather conditions. The Authorized Commander shall be made aware of thetimes to change states so that the decision to issue the order is made in a timelyfashion.
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RESPONSIBILITIES
2-3-8. Authorized Commander. Initially the Authorized Commander is theformation commander responsible for the operational plan. At any stage duringthe operation the Authorized Commander may delegate authority or transfer theresponsibility. For example, when one formation withdraws through anotherwhich is holding an intermediate position, it is normal for control to be transferredto the commander of the holding formation, who then becomes the AuthorizedCommander. Normally the procedure is to delegate responsibility for preliminarydemolitions to the Engineer Commander. The duties of Authorized Commandersand their staffs are:
a. preparation and distribution of the barrier plan to units;
b. designation of preliminary demolition targets that may have firingrestrictions, or require special security measures;
c. designation of reserved demolition targets and appointment of ademolition guard and firing party, including composition;
d. preparation and issuing of the Demolition Order;
e. orders the state of readiness, changes to it, and the demolition to befired;
f. orders emergency firing procedures as necessary;
g. notifies higher and all other interested headquarters if the authority is tobe delegated, or the demolition changed in classification from reservedto preliminary;
h. establishes special communications and/or liaison officers to pass theAuthorized Commander's orders; and
j. sets traffic priorities and advises units when routes or areas are closedto traffic.
2-3-9. Engineer Commander. The duties of the Engineer Commander are to:
a. advise to the Authorized Commander on the barrier plan and technicaldetails (preparation time, resources and expected results, etc);
b. reconnoitre, plan, prepare and execute demolitions;
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c. designate the engineer unit to provide the Demolition Firing Party;
d. assist the formation staff in the preparation of the DND 913 DemolitionOrder;
e. maintain of records of completed demolitions and demolitions inprogress;
f. ensure that the necessary stores are available;
g. provide a guard on preliminary demolitions if ordered; and
h. ensure that a reserved demolition is guarded until the arrival of theDemolition Guard.
2-3-10. Other Units. Infantry and/or armoured units may provide protectionfor engineer recce and work parties and form demolition guards when ordered.
PRELIMINARY DEMOLITION TARGETS
2-3-11. General. A preliminary demolition target can be executed as soonafter preparation as convenient on the orders of the officer to whom authority hasbeen delegated. These demolitions present fewer difficulties than reserveddemolitions and have the following advantages:
a. they can be completed by engineers or assault pioneers without therequirement for demolition guards or firing parties;
b. there is normally less interference by the enemy on our own troops andelaborate precautions against capture are not required;
c. a simple firing circuit may be used; and
d. demolition of a target (e.g., a bridge) can be executed in stages (e.g.,superstructure, piers, abutments) rather than simultaneously.
2-3-12. Control. All demolitions, reserved or preliminary, are subject tocontrol measures. Although preliminary demolitions are normally fired once theyare prepared; policital, tactical or geographical reasons may result in preliminarytargets being prepared and fired at a later date:
a. Prior to withdrawal, all preliminary demolitions may be prepared toState 1. Following the preparation of each target and depending uponthe tactical commander's orders, the prepared demolitions can be left
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secured by a guard, picket or patrol. They may also be turned over toan infantry or armoured unit. During the withdrawal, the prepareddemolitions may then be executed as required.
b. A particular facility or installation may be designated as a preliminarydemolition, however, due to its location it may be prepared and firedaccording to a timed schedule. For example a factory located in a cityfilled with refugees may be a preliminary demolition, with firingrestricted to when all refugees have been evacuated.
If any restrictions are placed on the execution of a preliminary demolition, a DND913 Demolition Order is prepared for that target.
EXECUTION
2-3-13. Progressive Preparations. When time for preparation is short, thedemolition can be prepared in progressive stages. An effective obstacle can thusbe created if preparations are halted at any stage. For example, the first step mightbe preparation of a single span (complete and ready to fire), before continuingwith other spans, piers or abutments. As later stages are completed, they areincorporated into the firing circuit.
2-3-14. Completion. The firing of a demolition does not necessarily completethe obstacle. Additional time may be required after the firing, to ensure thedemolition is complete as well as effective. For example, the cutting of a mainspan of a road bridge over a deep water obstacle, which achieves a 40 metre gap,may well complete the obstacle. However, in the case of closing a minefield lane(which may involve cratering), antitank mines would have to be laid after thecraters have been fired. In such cases, engineers will continue to requireprotection until it is completed. In the event of a misfire or only partialdestruction, the demolition guard shall continue to provide protection while thecorrective action is taken.
REPORTING
2-3-15. After the demolition, the effectiveness of the obstacle and the gapcreated shall be reported through the chain of command to the EngineerCommander.
2-3-16. If mines are laid to enhance the obstacle, these mines must be recordedon a Minefield Record (CF 1275) or on a Protective Minefield Record (CF 947),and this record will also be passed through the chain of command to the EngineerCommander.
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BARRIER HANDOVER
2-3-17. A change in the operational situation may require the transfer ofbarriers to another unit. This handover may be complicated by different languagesand differences in organization, training and barrier munitions if the units are fromother NATO nations. Barrier handover checklists are described inB-GL-319-001/FT-001, Engineers in Battle. When handing over prepareddemolitions to another unit, if a Demolition Order or obstacle folder was issuedfor the target, the form will be completed in accordance with the instructions.
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SECTION 4RESERVED DEMOLITIONS
GENERAL
2-4-1. The destruction of a reserved demolition target shall be controlled at aspecific level of command because it plays a vital part in the successful conduct ofan operation. There are few tasks in war where errors in orders, control, or timingcan have as serious consequences as in the execution of a reserved demolition.All demolitions along a reserved route are classified reserved. The number ofreserved demolitions shall be kept to a minimum. Reserved demolitions pose thefollowing problems to engineers:
a. they are usually kept open for traffic until the last moment, thereforequick and simple demolition techniques cannot be used;
b. the methods used to prepare the target for demolition shall be capableof withstanding weather, traffic vibrations, and enemy fire over a longperiod of time. Firing circuits shall be carefully placed and protected toavoid damage from passing vehicles, sabotage from pedestrians, orindirect fire; and
c. engineers who could be employed elsewhere have to remain at the siteawaiting the order to fire.
RESPONSIBILITIES
2-4-2. Demolition Guard Commander. The Demolition Guard Commanderis normally the officer commanding an infantry or armoured unit or sub-unittasked with protecting the reserved demolition. Responsibilities of the DemolitionGuard Commander are:
a. commanding the Demolition Guard and Demolition Firing Party;
b. approving the location of the firing points, which are located close tothe command posts;
c. securing the demolition site and providing protection to the reserveddemolition target and the firing party at all times;
d. controlling all traffic over or through the target;
e. passing orders in writing to the Demolition Firing Party Commander tochange the state of readiness and to fire the demolition;
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f. keeping the Authorized Commander informed of the state ofpreparation of the reserved demolition and the site situation;
g. reporting the results of the demolition to the Authorized Commander;and
h. maintaining a seniority list for that appointment and for the DemolitionFiring Party Commander in case of casualties.
2-4-3. Demolition Firing Party Commander. The Demolition Firing PartyCommander is normally an engineer officer or senior NCO commanding theengineer sub-unit tasked to provide the Demolition Firing Party and may wellhave been tasked to prepare the reserved demolition. However, for most reserveddemolitions, the preparation is completed by a Field Troop, and a Field Sectionremains behind as the Firing Party. The duties of the Demolition Firing PartyCommander are:
a. maintaining the state of readiness ordered for the reserved demolition;
b. advising the Demolition Guard Commander of the time required to:
(1) change the state of readiness, and
(2) complete the obstacle once the demolition is fired (i.e., mining),
c. maintaining a seniority list in case of casualties;
d. siting the firing point in consultation with the Demolition GuardCommander;
e. firing the demolition when ordered by the Demolition GuardCommander, and ensuring that the firing is successful. When there isno demolition guard and the Demolition Firing Party Commanderreceives orders to fire the demolition, other than those specified inparagraph five of the Demolition Order, the order shall be referred tothe Authorized Commander or to the Demolition Firing PartyCommander’s immediate superior;
f. reporting the results of the demolition by the fastest means possible tothe Demolition Guard Commander, or to whoever ordered the firing ifno demolition guard is provided; and
g. reporting the results of the demolition by completing the DemolitionOrder or Obstacle folder.
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COMMAND AND CONTROL
2-4-4. Communications. The Authorized Commander must ensure that thereis a clear channel whereby the order can be passed to a Demolition GuardCommander to change the state of readiness of a target and to fire it. This meansof communication will be positive, secure and known and understood by allconcerned. One of the following methods will usually be used:
a. normal command channels.
b. liaison officer with radio. This method provides a direct link to theAuthorized Commander and is often valuable as it permits theDemolition Guard Commander to concentrate on other aspects of histask.
c. radio allotted to the Guard Commander. This may be on the formationcommand net or a special net.
d. engineer net. Through the Demolition Firing Party.
e. artillery net. Through a Forward Observation Officer with theDemolition Guard.
f. line. A special line may be laid between the Demolition GuardCommander and the Authorized Commander.
g. dispatch rider. This method is useful in conditions of radio silence, andas an alternative to line.
h. Authorized Commander. The Authorized Commander may be on thesite to give the order in person.
2-4-5. Command. The Demolition Guard Commander commands all troopsat the reserved demolition site, including the Demolition Firing Party. TheDemolition Guard Commander makes the decisions concerning the layout of thedemolition site, including the locations of defensive positions, command posts,firing points, check points and routes throughout the site. An example site layoutis at Fig 2-4-1.
2-4-6. Main Command Post. Ideally the Demolition Guard Commander'scommand post shall be sited where it can best command the defence of thedemolition target from the home side. This may conflict with the requirements forthe demolition firing point which shall be close to or collocated with the command
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post. Usually some compromise is necessary as the Demolition GuardCommander and the Demolition Firing Party Commander shall be collocated.
2-4-7. Alternate Command Post. An alternate command post is required onthe far side and another alternate is required, sited on the home side.
2-4-8. Check Point. When units are withdrawing in contact with the enemy,problems of identification may arise. It is the responsibility of the withdrawingtroops to identify themselves to the Demolition Guard. A check point is alwaysestablished by the Demolition Guard. Military police or reconnaissance troopsmay be placed under command for this duty. Good communications are essentialbetween the check point and the Demolition Guard Commander. Each unitwithdrawing through the demolition is required to send a liaison officer to thecheck point well in advance of the unit.
2-4-9. Refugee Control Points. For refugees on foot and in vehicles, acheckpoint manned by military police on the far bank and a release point on thehome bank may be required. The control of refugees is the responsibility of theDemolition Guard Commander. Refugee traffic shall be halted off the route, andthen escorted across the target in groups to the release point. Refugees will not beallowed to interfere with the withdrawing forces or with the demolitionpreparations.
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Fig 2-4-1 Example reserved demolition site layout
FIRING POINTS
2-4-10. Main Firing Point and Alternates. The main and alternate firingpoints are normally as close to the demolition target as possible to provideobservation. The firing point shall provide protection to the firing party from theeffects of blast and falling debris. Safety distances that shall be followed during
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peace and operations are detailed in Chapter 4. As a minimum, there will be twofiring points; the main on the home bank and an alternate on the far side. Analternate firing point on the home side shall also be sited if possible. The mainfiring point will be manned continuous-ly. Manning of the alternate firingpoint(s) will be based on the judgement of the Demolition Guard Commanderconsidering the target size, manpower, the time required to change to State 2, andthe threat. Normally the second-in-command of the Demolition Guard and thesecond-in-command of the Firing Party are collocated at the alternate commandpost and firing point on the home side.
2-4-11. The firing point is sited so that the Demolition Firing Party Commandercan:
a. be easily accessible to the Demolition Guard Commander for orders tochange the state of readiness and to fire the demolition;
b. communicate with the firing party; and
c. observe the entire target. Siting of the firing points will also take intoaccount the proximity of the electro-magnetic emitters (e.g., air defenceradar) and their potential impact on firing circuits and electricdetonators.
FIRING PROCEDURES
2-4-12. Firing Procedure. The normal procedure for firing a reserveddemolition is as follows:
a. the Demolition Guard Commander reports to the AuthorizedCommander that the demolition is prepared to State of Readiness 1(SAFE), and the time required to change to State 2 (ARMED), which isrecorded on Demolition Order;
b. the Authorized Commander orders the change in State of Readiness toState 2 (ARMED). The Demolition Firing Party Commander's copy ofthe Demolition Order (Copy 2) is completed by the Demolition GuardCommander;
c. the Authorized Commander issues the order to fire the demolition to theDemolition Guard Commander;
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d. the Demolition Guard Commander passes the order to fire to theDemolition Firing Party Commander by signing the Demolition FiringParty Commander's Demolition Order (Copy 2); and
e. the Demolition Firing Party Commander fires the demolition, checksthat the firing is successful, and reports the results to the DemolitionGuard Commander. Any required mining or booby-trapping is thencompleted.
2-4-13. Failure. If there is a failure or partial failure of the demolition, thefiring party shall take immediate steps to rectify the fault and if necessary reset thecharges. The demolition guard, if provided, shall remain in position until thedemolition has been successfully completed.
2-4-14. Reports. The results of a reserved demolition are reported as follows:
a. the Demolition Guard Commander reports the results of the demolitionto the Authorized Commander, with Part III of the Demolition Ordercompleted (Copy 1); and
b. the Demolition Firing Party Commander completes the DemolitionReport pages of the Obstacle Folder (if used), as well as Part III of hisDemolition Order (Copy 2), and forwards it through the engineer chainof command to the Engineer Commander.
2D-1. The Obstacle Folder-Germany (CF 765) is based on STANAG 2123. Itis specific to operational planning for the defence of North-West Europe, howeverthis does not preclude the use of it for targets planned during training or onoperations elsewhere. It gathers in one document, all of the information relevantto a specific demolition target. On completion of the folder, the informationcontained within is classified as NATO CONFIDENTIAL, otherwise it remainsNATO UNCLASSIFIED while blank.
2D-2. The Obstacle Folder is for targets which have been reconnoitered wellin advance. Early reconnaissance permits the determination of charge sizes andlocations as well as the storage of the required explosives, accessories and minesin a nearby ammunition storage facility.
2D-3. In Germany, numerous potential demolition targets were constructedwith chambers ready to receive explosives, and buried conduits for firing circuits,as described in Section 4, Chapter 5.
CONTENTS
2D-4. There are five parts to the folder: the target location, supply ofmunitions and stores, technical instructions for the target preparation,handover/takeover procedures, and the demolition report. The table of contents isfound on the inside of the back cover page.
2D-5. The folder consists of white and light blue pages. The light blue pagesmay be detached and distributed as follows:
a. pages 3, 7, 8, 9, and 15 - for use by the commander of the party detailedto pick up the barrier material;
b. page 31 - for retention of the Unit handing over the target; and
c. pages 33 and 34 - for use by the Demolition Firing Party Commander toreport the results to the next superior officer (e.g., Demolition GuardCommander).
2D-6. The white pages are to remain in the folder. If there is insufficientspace to enter the information, insert pages can be used. In such cases, the words"see page..." are to be inserted at the appropriate place. The insert page is to be
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placed immediately after the page to which it refers. Convenient pockets areincluded for the key to the ammunition storage facility and the Demolition Order.
2D-7. All subject matter in the obstacle folder is to be completed in languagesagreed for the folder: English, French or German. Notes on maps, plans, sketches,etc., are to be in one language only, with a translation of relevant items intoanother language at the page provided.
DISTRIBUTION
2D-8. These folders are made in a very limited number of copies. One copywould be issued through the chain of command to the Section or TroopCommander responsible for a particular target.
COMPLETION AFTER FIRING
2D-9. After completing the obstacle, the Demolition Firing Party Commanderreports the results of the demolition to the Demolition Guard Commander (if thereis one) using pages 33 and 34, and through the engineer chain of command bycompleting pages 35 and 36 of the folder.
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ANNEX E - DEMOLITION ORDER (DND 913)
Fig 2E-1 Demolition Order (DND 913) front
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40 B-GL-361-008/FP-003
Fig 2E-1 Demolition Order (DND 913) back
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B-GL-361-008/FP-003 41
CHAPTER 3SERVICE DEMOLITION STORES AND EQUIPMENT
SECTION 1GENERAL
SCOPE
3-1-1. This chapter describes the characteristics and uses of demolition storesand equipment not previously covered in B-GL-320-009/FP-001, including:
a. shaped charges and military explosives for specific tasks;
b. electrical initiating accessories and equipment;
c. commercial explosives;
d. miscellaneous equipment; and
e. NATO demolition stores.
EXPLOSIVES
3-1-2. The theory of explosives is explained in B-GL-320-009/FP-001, as arenon-electric accessories.
3-1-3. Types. Explosives are available in various shapes and sizes for varioustasks. The various types of explosives which may be encountered are explained inAnnex A to this Chapter. Logistic and packaging details are in Annex B to thisChapter.
3-1-4. Danger: All explosives are not the same. Engineers and AssaultPioneers must understand the properties of the explosive being used.
3-1-5. Commercial explosives. Commercial explosives can be madeavailable through the supply system. They are usually used for a specific task,when one or more of their properties are superior to those of service explosives orif service explosive stocks have been depleted. In these cases, detailedspecifications are required. Civilian explosives must never be mixed with serviceexplosives as the main charge. The characteristics of commercial explosives areoutlined in Annex C to this Chapter.
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3-1-6. Improvised explosives. The fabrication of improvised explosives andcharges may be required in some situations and is explained in Annex D to thisChapter.
NATO DEMOLITION STORES
3-1-7. There are a variety of explosives, charges and demolition accessories inuse by the other NATO countries. More information is contained in AOP-19Land Forces Explosives and Demolition Accessories Interchangeability CatalogueIn Wartime (NATO).
NATO INTERCHANGEABILITY SYMBOL
3-1-8. Fig 3-1-1 shows the NATOinterchangeability symbol whichindicates (for demolition stores) that theitem complies with a NATOstandardization agreement, and isfunctionally interchangeable with anyitem of similar function bearing thesymbol, when used with otherdemolition accessories also bearing thesymbol. Fig 3-1-1 NATO interchangeability
symbolCOMPATIBILITY OF DEMOLITION ACCESSORIES
3-1-9. Fig 3-1-2 is a summary of the compatibility of demolition accessories.It shows, for example, if the non-electric detonators of one nation can be usedwith the safety fuse of another nation. This chart may be out of date in some casesbecause new items may have been introduced. It will be amended as correctinformation is available. Symbols used in Fig 3-1-2 are shown in the legend, anda blank at the junction of particular items indicates compatibility
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B-GL-361-008/FP-003 43
Fig 3-1-2 Summary of compatible demolition accessories
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B-GL-361-008/FP-003 45
SECTION 2SHAPED CHARGES
THEORY
3-2-1. Shaped charges use explosive power to penetrate into hard targets suchas armour plate and concrete. A typical shaped charge concentrates the energyfrom the detonation and the moving shock wave to a specific point on the target.A "V" shaped cavity inverts and directs the shock wave while the standoffdistance provides time for the inversion to occur. The explosives used in shapedcharges are generally pressed or cast with a high velocity of detonation. Thehigher the velocity of detonation and detonation pressure, the more effective thepenetration.
Fig 3-2-1 Shaped charge and target
3-2-2. When the detonator initiates the explosive charge, the detonation wavepasses over the liner and liquefies it. The liner material is then accelerated (Fig 3-2-2). When the liner material converges at the centre line or axis of thedetonation, it is squeezed out at high velocity, thus forming a jet. The materialclose to the apex of liner moves at a much higher velocity than the material towardthe base of it. The remainder of the liner forms a heavy solid slug which followsthe jet at a much slower velocity.
3-2-3. The intense pressure created by the jet causes the penetration of thetarget. The pressure applied by a shaped charge is in the order of severalmegabars which is well into the ballistic range for most materials.
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Fig 3-2-2 Shaped charge jet formation
Fig 3-2-3 illustrates the response of thetarget to a shaped charge jet. Penetrationoccurs as the material flows out of thehole. The material dislodged in thedeeper part of the hole flows out alongthe walls. The distance between theshaped charge and the target is criticalbecause there must be sufficient room toform the jet, but not too great or the jetwill stretch and dissipate. Typical stand-off distances are between three to six
Fig 3-2-3 Shaped chargepenetration
times the charge diameter. Penetration is highly dependent on the target material.For steel it is normally around four to six times the charge diameter, but preciselymanufactured shaped charges can penetrate as high as 10 or 12 times the chargediameters.
3-2-4. The Canadian Forces use both conical and linear shaped charges(above). The conical shaped charge is round in construction and creates a pointpenetration. Conical shaped charges penetrate deeper than the linear chargesbecause the energy from the explosion is focussed at a single point. Theexplosion in the linear shaped charge is focussed along a line, which forms a longlongitudinal jet that slices through the target making a linear cut.
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CONICAL SHAPEDCHARGES
3-2-5. Conical shaped chargesare used primarily to bore holes inearth, masonry, concrete and inpaved and unpaved roads. Theymay also be used to disable troopsinside fortifications. Thefollowing conical shaped chargesare currently used: Fig 3-2-4 Types of shaped charges
a. Charge Demolition, 15 lb, M2A4;
b. Charge Demolition, 40 lb, M3A1; and
c. DREScavator (a conical shaped charge based on a plastic container anda steel liner. This will be used with Trigran and will be similar to theCharge Demolition, Linear Shaped, 10 kg, Trigran C24).
3-2-6. Logistical data for these charges is found in CFTO C74-300-DO1/TA-000.
3-2-7. Effectiveness. The effectiveness of the conical shaped charges isoutlined below.
EffectivenessSer Target SpecificationsM2A4(15 lb)
M3A1 (40lb)
(a) (b) (c) (d) (e)
1 Armourplate
PenetrationAverage hole diameter
30.5 cm 3.8 cm
50 cm 6.35cm
2 Reinforced concrete
Maximum wall thicknessPenetration depthAverage hole diameter
91.5 cm76.2 cm 7.0cm
152 cm152 cm 9 cm
Fig 3-2-5 Conical shaped charge effectiveness
CHARGE DEMOLITION, NO 1, 6 INCH, BEEHIVE, MK3
3-2-8. The Charge Demolition, No 1, 6 inch, Beehive, MK3 has been replacedby the Charge Demolition, 15 lb, M2A4.
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Fig 3-2-6 Methods of arming (with and without M1A4, adapter)
CHARGE DEMOLITION, 15 LB, M2A4
3-2-9 Description. The M2A4 shaped charge (Fig 3-2-7) is less sensitive todetonation by small arms fire than the M2A3 version due to changing the boosterfrom Pentolite (M2A3) to Composition A3. It consists of a moisture resistantfibre container with a cylindrical lower portion and a conical upper portion formedin one piece. The dimensions of the charge body are 30.35 cm high, bottomdiameter of 17.3 cm and a top diameter of 5.23 cm. The stand-off distance isprovided by a fibre sleeve. The top of the tapered sleeve fits into the bottom ofthe charge while the scalloped bottom provides a firm base for the charge. Thestand-off sleeve is placed around the charge body for shipping. It contains 4.5 kgof Composition B, with a cavity to accept the 50 gram Composition A3 booster.The detonator well protrudes into the booster. The charge liner is made of glass.
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B-GL-361-008/FP-003 49
Fig 3-2-7 Charge demolition, 15 lb, M2A4
3-2-10. Preparation. The charge is to be armed only by using a No 12 non-electric, or M6 electric detonator. It may also be used in conjunction with theM1A4 adapter. The adapter is used because the threaded deton-ator well on top ofthese charges is larger than the in-service detonators.
CHARGE DEMOLITION, 40 LB, M3A1
Fig 3-2-8 Charge Demolition, 40 lb, M3A1
3-2-11. Description. The M3A1 charge (Fig 3-2-8) is an improvement overthe M3, being less likely to detonate due to small arms fire. It is used for rapidexcavation of boreholes and general demolitions. The metal charge body is 39.1cm high and 24.1 cm in diameter. The steel cone has a internal angle of 60
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degrees. Stand-off is provided by a steel frame which consists of a 3.8 cm steelband with sections bent inward to provide a seat upon which the charge sits andthree steel legs welded to the outside of the band to provide a 35.8 cm stand-off.A set screw is provided to secure the charge in the stand-off frame. The maincharge is 13.6 kg of Composition B and has a cavity for the 50 gram CompositionA3 booster.
3-2-12. Preparation. The M3A1 is armed using No 12 non-electric or M6electric detonators only, due to the No 12 electric detonator being too large to fitin the detonator cavity. The threaded detonator well accepts the M1A4 adapter.
DRESCAVATOR SHAPED CHARGE
3-2-13. General. The DREScavator demolition charge is the proposed newgeneration conical shaped charge that will replace the present items now in use. Itis being tested and is expected to be available in the near future. It is planned thatthe container will be prefilled with Trigran. It is presently assembled on site andconsists of the following;
a. container, demolition, conical, filled with Trigran;
b. liner, conical steel; and
c. water or motor oil as required.
3-2-14. Assembling the Charge. Above freezing temperature (0°C) add waterand below freezing temperature add motor oil (any grade), to the Trigran,occasionally tapping the container gently to ensure that all voids are filled.
3-2-15. Important. Do not use liquids other than water or motor oil as theymay react with, or breakdown the Trigran. If the charge is transported in theprepared state, settlement of the Trigran may occur causing air voids inside thecontainer.
3-2-16. Preparation. Mold a minimum of 140 grams (¼ block) of C4 around adouble thumb knot on a detonating cord lead. Place the priming charge into theTrigran ensuring good contact. The charge is initiated using an electric or non-electric detonator connected to the detonating cord lead.
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Fig 3-2-9 Adapter, priming, M1A4
ADAPTER, PRIMING, M1A4
3-2-17. Description. The prim-ing adapter M1A4 (Fig 3-2-9) is aplastic hexagonal shaped devicethreaded to fit in the standardthreaded detonator cavities used inthe M2A4 (15 lb) and M3A1 (40lb) shaped charges. A shoulderinside the threaded end is largeenough to accept safety fuse anddetonating cord, but too small topermit passage of a detonator. Theadapter is slotted along its lengthto permit easy and quick insertionof electric detonator lead wires
Fig 3-2-10 Use of M1A4 adapter
LINEAR SHAPED CHARGES
3-2-18. Linear shaped charges are primarily used to cut main support membersof bridges. The following linear shaped charges are available:
a. Charge Demolition, No 14, 11 lb, MK 1;
b. Charge Demolition, Necklace, L1A1; and
c. Charge Demolition, C126, Linear Shaped, 10 kg, Trigran C24(DREStructor).
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CHARGE DEMOLITION, NO 14, 11 LB, MK 1
3-2-19. The Charge Demolition, No 14, 11 lb, MK1 (below) is commonlyknown as the Hayrick. The charge body is made from sheet steel. The bottom isclosed by a 47 mm mild steel liner, which is bent into an inverted V with an angleof 55 degrees. There is a steel tower welded centrally on top with a filling holeclosed by a pressed in cap. There are steel hinges on each end of the charge whichare used to join the charges directly together or by using the link adjustable. Itcontains 5.1 kg of explosives consisting of 50% RDX and 50% TNT, and aperforated tetryl pellet that acts as a primer/booster, positioned centrally in thetower with a bolt passing through the holes of the tower and the pellet. Totalweight of the charge is 9.3 kg.
Fig 3-2-11 Charge Demolition, No 14, 11 lb Mk1(Hayrick)
3-2-20. Preparation. When the hayricks have been positioned around thetarget, the bolts are withdrawn and a length of detonating cord is fed through thetowers of all hayricks for simultaneous detonation.
3-2-21. Effectiveness. With no stand-off distance other than that inherent inthe design, and with charges placed on opposite sides of the target, the hayrickwill cut 200 mm of laminated steel.
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Fig 3-2-12 Methods of use-Charge Demolition, No, 14 (Hayrick)
Fig 3-2-14 Charge Demolition, No 14(Hayrick), configuration
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CHARGE DEMOLITION, NECKLACE, L1A1
3-2-22. Description. The Charge Demolition, L1A1 is made up of fivehayricks and the hardware to attach it to the target. The complete assemblyconsists of the following items in a single container:
a. Charge Demolition, No 14, 11 lb, MK1: quantity five;
b. Clamps Demolition, Necklace, MK1: quantity;
c. Links Adjustable Demolition, Necklace, MK1: quantity two (2); and
d. nails, 150 mm (6 inch): quantity ten (10).
3-2-23. Preparation. It is armed as per the Charge Demolition No 14, 11 lbshaped charge.
3-2-24. Effectiveness. Using the full necklace, the charges will cut a 25 mmsteel plate from a stand-off distance of up to 1 m.
CHARGE DEMOLITION, C126, LINEAR SHAPED, 10 KG, TRIGRANC24
3-2-25. Description. Also known as the DREStructor, the C24 DemolitionCharge was designed as a low cost linear shaped charge for structural demolitions.It is assembled on site and consists of the following:a. ContainerDemolition, C126, filled with ten kg of Trigran;
b. Liner Steel, C1; and
c. water or motor oil as required.
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3-2-26. The Container DemolitionC126, is an olive drab, mediumdensity, polyethylene container. It is368 mm long, 172 mm wide, and 321mm high. There is a central towerwhich is screw threaded externally toaccept the filling cap. A cloth handleis formed off each side of the tower.When the cap is fitted to the charge, amolded seal and gasket inside the lippresses against the top of the tower toprovide a water tight seal. The capextends inside the tower and into the Fig 3-2-15 Container Demolition, C126
trigran charge. Four molded plastic or nylon fasteners are contained inside thecap for use in securing the liner to the charge.
3-2-27. The bottom of the charge is formed in the shape of an inverted "V" withan interior angle of 60 degrees. A solid plastic strip along each lip of the "V" hasbeen perforated by two 14 mm holes for securing the metal liner to the charge.The C1 liner (Fig 3-2-16) is made from 4.4 mm steel and fits into the inverted "V"of the container. The liner is perforated by eight 14 mm holes. The top four holes(two on each side) match up with the four holes in the bottom edges of the C126container. The bottom four holespermit attachment to the target usingwire or rope. Flanges on oppositesides of the liner allow it to be attachedto the target by use of a bolt gun or byinsertion into prepared rails.
Fig 3-2-16 Liner steel, C1
Fig 3-2-17 Container Demolition,C126 and liner C1,schematic
3-2-28. Charge Assembly. The charge is assembled in a similiar manner to theDREScavator.
3-2-29. Preparation. To arm the charge:
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a. using the projection of the cap, clear a path in the mixture. Ensuring thethreads and bearing surfaces are free of debris and explosive particles,screw the cap securely onto the container;
b. mold a minimum of 140 grams (¼ block) of C4 plastic explosivesaround a double knotted lead of detonator cord. Press it into the capcup ensuring the cup is completely filled; and
c. attach the liner to the charge container by inserting the four plasticfasteners.
3-2-30. Effectiveness. The assembled charge produces a cut in steelapproximately 600 mm long and 130 mm deep near the charge centre. Inreinforced concrete, reinforcing bars up to a depth of 115 mm will be cut belowthe centre of the charge. Non-reinforced concrete will be breached to a greaterdepth and length. The depth of cut at the ends is reduced in comparison with thecentre. Two (2) DREStructors positioned opposite each other will destroy areinforced concrete beam up to one metre in thickness.
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SECTION 3SPECIFIC TASK MILITARY EXPLOSIVES
TRITONAL GRANULATED (TRIGRAN)
3-3-1. Description. Granulated Tritonal (Trigran) is a high energy blastingexplosive in prill form used for cratering operations. It is also used in conjunctionwith the DREScavator and DREStructor. Trigran is a homogeneous mixture of80% TNT and 20% atomized aluminum in the form of solid spherical particles ofapproximately 3 mm nominal diameter. Trigran is water resistant. It flows as aliquid and detonates efficiently inhot or cold environments. It isinexpensive compared to C4 plasticexplosives.
3-3-2. Trigran comes in 9 kgjugs made of black, high densitypolyethylene and the jug has aminimum weight of 418 grams.The design includes a 76 mmdiameter pour-ing spout, fitted witha screw threaded plastic cap and acarrying handle. Fig 3-3-1 Container, Trigran
3-3-3. Preparation. Trigran charges are armed with a priming charge of highexplosive. A minimum of one-quarter (3) block of C4 plastic explosives isnormally molded around a double thumb knot of detonating cord.
3-3-4. Effectiveness. Trigran has a velocity of detonation of 4000 m/s, andwhen a liquid is used to fill the air voids, it is increased to 6000 m/s. Throughextensive trials, Trigran has been found to be an excellent cratering explosive andwhen used as directed, the shaped charges work very effectively.
CHARGE DEMOLITION FLEXIBLE, "DETASHEET C"
3-3-5. Description. Certain tasks require explosives in special shapes orconfigurations. Detasheet "C", olive drab in colour, is the military version ofDetasheet and is made to military specifications. Detasheet is a flexible highexplosive composed of a mixture of 63% PETN, 8% Nitrate of Calcium, and anelastomeric binder. It has a velocity of detonation of 7000 m/s. Detasheet is usedin special charges for steel cutting as described in Chapter 6.
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3-3-6. Preparation. Whenpreparing Detasheet, it shall be cutwith a knife and armed by one ofthe following methods:
a. first method (at right):
(1) cut a notchapproximatelyfour cm long andsix cm wide in theDetasheet, insertthe detonator fully,and secure thedetonator withtape; or
Fig 3-3-2 Arming Detasheet
Danger.Explosives shall be cut with a knife on a non-sparking surface. Do notuse shear type instruments
(2) place the detonator on top of the Detasheet and secure it withanother strip of the explosive; or insert the end of the detonatorapproximately 40 mm between two sheets of the explosive.
b. second method: If usingdetonating cord only, theDetasheet may be primedby tying a Uli knot (shownhere) and inserting it in thesame way as a detonator.
3-3-7. Description. The satchel charge is used for general demolitionpurposes, including underwater operations. It may not be submerged for morethan three hours. Several charges connected together can be floated
3-3-8. The satchel chargeconsists of a haversack packedwith 10 individual ChargeDemolition, MK 35 Mod 1, eachconsisting of a 0.9 kg block of C4explosive contained in a canvascharge bag. Total weight is 12.5kg. The booster and explosivelead consists of 2.74 m ofreinforced detonating cord.Approximately one metreof the detonating cord is looped toform a 0.3 m booster in theexplosive charge and theremainder extends out to form theexplosive lead. The explosive leadis looped under the webbing onone face of the charge bag. Eachcharge has a securing sash cord(1 m) and a flat hook for lashing itto obstacles.
Fig 3-3-5 Satchel charge explosive lead
3-3-9. The haversack is a Field Pack Canvas MK 4, Mod 1 and is made ofgrey cotton treated to be waterproof, fireproof and mildew resistant. The shoulderstrap is equipped with a snap hook and fastener which can be adjusted from 50 -127 cm. The pocket on the back of the haversack holds one Bladder Assemblywhich is issued with each satchel charge. The towing ring is secured to thebottom of the haversack. The satchel charge can be lashed to an obstacle with thefive metre cotton securing cord and the two flat hooks.
3-3-10. Safety Precautions. The following safety precautions shall beobserved:
a. the satchel charge contains high explosive and therefore should beprotected from high temperatures and severe drops and jolts; and
b. poisonous gases are produced when detonated, so an enclosed areamust be ventilated prior to re-entering.
EXPLOSIVE TRAINING CHARGE, C2/C2A1
3-3-11. Description. The C2 and C2A1 explosive training charges areCanadian designed and used to simulate explosive demolition charges during
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training. The complete charge shown in Fig 3-3-5 consists of the followingcomponents:
a. The charge container is made of molded uncoloured polyethylene andis designed to accept the bursting charge and fuse cavity with thequickmatch assembly attached.
c. The fuse cavity is made of a resin rubber molding compound and isthreaded internally to accept the igniter electric adapter of differentfiring devices.
c. The quickmatchassembly consistsof strands of wovenrayon cordimpregnated in aquickmatchmixture, looped andinserted through thehole of a corkwasher.
d. The retainingsleeve is made of aresin rubbermolding compoundand secures thecharge container tothe fuse cavity.
Fig 3-3-6 Explosive training charge C2/C2A1
e. The igniter electric adapter is molded of polyethylene. It is threadedto fit into the fuse cavity and has a central fire channel to accept anigniter electric. The C2A1 differs from the C2 in that the ribs on theexternal surface of the igniter electric have been removed to facilitateinsertion of the C2A1 into the M18A1 practice mine.
f. The closing plug with safety fuse adapter of molded polyethylene isused to seal the fire channel in the igniter electric adapter duringstorage and transport. To operate, the fuse adapter portion is inserted inthe fire channel and used with Fuse Blasting Time, M700.
g. The bursting charge consists of approximately 1.5 grams ofsulphurless powder.
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3-3-12. Preparation. This training charge can be armed with:
a. Fuse Blasting Time M700 (Safety Fuse):
(1) remove and retain the closing plug/safety fuse adapter,
(2) insert the safety fuse into the safety fuse adapter at the end remotefrom the plug, and
(3) insert adapter and safety fuse end into the hole in the igniterelectric adapter. Ensure that the open end of the safety fuseprotrudes just beyond the end of the fuse adapter.
b. Igniter electric.
(1) remove and discard the closing plug for the igniter electricadapter,
(2) insert the igniter electric into the hole in the igniter electricadapter, and
(3) attach the igniter electric to the firing device or to the electricalsupply (make sure that the switch is off).
The flame from either of the above method ignites the quickmatch fuse, whichignites the bursting charge and causes the charge container to burst with a mildexplosion.
FUSE INSTANTANEOUS, L1A1
3-3-13. Fuse Instantaneous L1A1 consists of a twisted yarn coated withsulphurless mealed powder wound with one "Durafil" yarn and protected by alight brown polythene covering. It has an outside diameter between 4.95 and 5.20mm and has an identification marker in the form of a raised ridge that runs alongthe length for night identification. Fuse Instananeous L1A1 comes in 150 mlengths and has a burning rate of not less than 33.5 metres a second at 16o C. Itfunctions within a temperature range of -32o to 52o C.
3-3-14. Fuse Instantaneous L1A1 is used to join the firing device to the maincharge when using booby traps, and in battle noise simulation. The followingsafety precautions are to be observed:
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a. avoid sharp bends, kinks and stretching;
b. handle carefully in cold weather to avoid breaking the protectivecovering or the powder train. In rainy or damp weather keep theconnections dry by taping; and
c. tape all loose or cut ends and keep unused fuse in its original packaginguntil required.
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SECTION 4ELECTRICAL ACCESSORIES AND EQUIPMENT
ELECTRIC DETONATORS
3-4-1. Electric detonators initiate explosives upon command of an electricalsource. The four (4) electric detonators in service are:
a. Cap Blasting Electric, Commercial No 12;
b. Cap Blasting Electric, Commercial C3;
c. Cap Blasting Electric, M6; and
d. Cap Blasting Electric, M4.
When handling electric detonators be sure to follow procedures outlined inChapter 4.
3-4-2 Both the No 12 and theC3 electric detonators are regularstrength, high fire energy detonators.The C3 detonator is an improvedversion of the No 12 detonator inthat it has less lead ozide butprovides the same output. Theloading of the PETN and lead azidehas been changed to make it safer tomanufacture. The C3 detonator willreplace the No 12 detonator oncestocks have been depleted. Briefdescriptions appear here.
3-4-3. The M4 and M6 electricdetonators are American highstrength electric detonators and aredesigned to be used in conjunction
Fig 3-4-1 Typical electric detonator
with the M1A4 adapter. The M6 electric detonator is used to initiate the 15 lbshaped charge, the 40 lb shaped charge and the Bangalore Torpedo. The M4electric detonator is identical to the M6 except the lead wires are 30.4 m (100 ft)long for use in the M18A1 Claymore antipersonnel mine.
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3-4-4. Igniters Electricignite safety fuse, explosivetraining charges and blackpowder upon command of anelectrical source. The electricigniter that is presently inservice is the Igniter, TimeBlasting Fuse, Electric, C2(igniter electric). It consists ofa cylindrical aluminum bodycontaining a match headcomposition (15 mg) formedaround a bridge wire. Twolead wires extend from one endof the body. The other end isopen to receive the safety fuseor instantaneous fuse.
Fig 3-4-2 Igniter, time blasting fuse, electric,C2 (igniter electric)
DEMOLITION SET, C1, NON-EXPLOSIVE, WITH EQUIPMENT
3-4-5. The following items are included in the check list for the DemolitionSet, C1, and are demanded separately:
a. blasting machine, ZEB/C100S;
b. reeling machine, cable hand, without reels, quantity two (2);
c. knife, pocket, C5;
d. crimper, blasting cap, No 4, plier type, with integral fuse cutter;
e. pliers, lineman, with sidecutter;
f. insulation tape, electrical, cotton, 19 mm, thermo setting adhesive;
g. ohmmeter, portable;
h. cable assembly set pricker; and
j. reel, cable steel, 230 mm flange diameter, 196.85 mm inside traverse,203.2 mm maximum outside diameter.
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BLASTING MACHINE, ZEB/C100S
3-4-6. Description. The blasting machine ZEB/C100S is a portablecondenser type exploder used to provide power required for the initation ofelectric detonators and igniters. It consists of a light metal casing with a drivingshaft fitted to the casing cover which accepts a detachable crank handle. Thecrank handle is held in position by a blocking lever. An ignition push button andtwo terminals for the demolition cable are located on the top of the casing. Theterminals are fitted with an insulating body to prevent short circuiting between thecasing and the demolition cable. Two sight glasses are also located on the top, aneon discharge lamp which indicates full ignition and a filament lamp for theexploder testing system. The blasting machine will operate with a maximumcircuit resistance of 260 ohms. It can be used in temperatures of -46o C to 70o C.The set includes the blasting machine, two crank handles, a carrying case with aspare tube containing two filament lamps and case, a battery case and lampchanging key.
3-4-7. Testing. The test forfunctioning and maximumcapacity must be conducted priorto every operation as follows:
a. open the case andremove the crank handlefrom the side pocket;
b. push the blocking lever back and hold it at stop;
c. place the crank handleonto the driving shaftand release the blockinglever; Fig 3-4-3 Blasting machine, ZEB/C100S
d. turn the crank handle until the neon discharge lamp (at right next toterminals) glows, indicating that the ignition condenser is loaded; and
e. push the blocking lever to stop, remove the crank handle in an upwardmotion and allow the blocking lever to slide back to the originalposition. During this operation observe the filament lamp (next tofiring button). If the filament lamp glows brightly for a short time itindicates that the blasting machine has reached its maximum capacity.When the voltage of the blasting machine decreases to approximately80%, the filament lamp will not glow. By detaching the crank handle
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and releasing the blocking lever, the blasting machine is discharged andfree of current.
3-4-8. Operation. To operate the blasting machine:
a. connect the demolition cable to the terminals;
b. charge the blasting machine as per the procedure described in thetesting paragraph;
c. push the ignition button down as far as possible to effect ignition;
d. push the blocking lever back to stop and detach the crank handle; and
e. disconnect the demolition cable from the terminals.
Check the satisfactory operation of the blasting machine by turning the crankhandle and observing the glowing of the right hand neon discharge lamp.
3-4-9. Filament Lamp Replacement. To replace the filament lamp:
a. use the key to remove the sight glass of the filament lamp in a counterclockwise direction;
b. slip the slotted handle end of the key onto the filament lamp, pressingslightly, and take out the lamp without turning. The lamp has a pinplug (not a screw) so that a turning movement must be avoided whenremoving the filament lamp;
c. insert the replacement lamp in the slotted end of the socket; and
d. replace the "O" ring and the sight glass.
3-4-10. Maintenance. This condenser type blasting machine requires nospecial maintenance. To ensure satisfactory contact, the terminals shall always bekept clean.
OHMMETER, ZEB/WO, TEST SET
3-4-11. Description. The ZEB/WO ohmmeter is a portable instrument used totest for continuity and to measure resistance in electric detonators, igniters,demolition cable and electrical firing circuits. All exterior components of theZEB/WO ohmmeter have been tightly sealed to prevent water penetration. Thebattery compartment is secured by a screw cap on the left side of the meter. The
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B-GL-361-008/FP-003 67
two terminals on top of the ohmmeter have undetachable knurled nuts. Themaximum transmitted testing current is 18 milli-amps, however, if the ohmeter isdamaged a built in safety features will prevent a current in excess of 50 milliampsfrom being generated and transmitted. The ohmmeter set includes: ZEB/WOohmmeter, leather carrying case, battery compartment key, shorting link and a 1.5volt, size AA battery.
3-4-12. Pre-check. Theaccuracy of the ohmmeter dependson the voltage of the currentsource. The ohmmeter shall be re-set if the voltage of the batterydecreases or if the battery has beenreplaced. The followingprocedure applies:
Fig 3-4-4 Ohmmeter, ZEB/WO
a. open the terminals ensuring that the ohmmeter is not connected to ortouching any object. The indicator must point to the infinity scale.Any deviation can be corrected by carefully turning the slotted screwinserted in the middle of the casing cover at the front (the screw may beadjusted with the battery key or any suitable tool);
b. short circuit the terminals by using the shorting link. The indicatormust reflect to the zero reading scale. Any deviation can be correctedby turning the slotted screw at the bottom right hand corner of theohmmeter. Battery fluctuations plus or minus 10% can be corrected. Ifthe indicator cannot be set to zero, the battery shall be replaced; and
c. remove the shorting link from the terminals.
3-4-13. Measuring resistance. To measure resistance in electric detonators,demolition cable or a firing circuit, the following procedures will be followed:
a. connect the open ends of the electric detonator, demolition cable, orfiring circuit to the terminals on the ohmmeter. The ohmmeter willindicate the exact resistance;
b. to determine what the total resistance of the firing circuit should be, addthe cable resistance to the resistance of all individual items connected inthe circuit. If the ohmmeter reading exceeds the calculated resistance,this indicates the presence of added resistance in the contacts. If themeasured value falls below the calculated value, this indicates currentmay be leaking through an improper electrical connection. A break inthe circuit is indicated if the ohmmeter indicates no reading at all; and
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68 B-GL-361-008/FP-003
c. after terminating the test, disconnect the wires from the terminals.
3-4-14. Replacing the battery. If it is not possible to adjust the indicator tozero, the battery shall be replaced by:
a. turning the screw cap of the battery compartment counter clockwise(using the key provided);
b. removing the non-serviceable battery;
c. inserting a fresh battery negative pole down, so the positive pole willmake contact with the brass on the screw cap;
d. replacing the screw cap; and
e. the ohmmeter is then checked and adjusted if required, as describedabove.
PRICKER CABLE SET
3-4-15. The pricker cable set consists of a red and black cable, 2 m in length,fitted to pricker clamps. A banana plug is secured at the opposite end whichconnects to the terminals on the ohmmeter. The pricker cable set is used to locatefaults in a firing circuit. The fault finding procedure is described in Chapter 4.
DEMOLITION CABLE
3-4-16. Description. The standard cable used for demolition purposes consistsof a cable with two conductors that are twisted together. Each conductor is 14AWG and consists of 19 copper cholorosuphonated wire strands, with each strandbeing 27 AWG. The conductors are polyethylene insulated with one being blackand the other tan. The cable is available in 300, 600, 900 and 1200 m lengths.The voltage capacity is 600 V and is rated to a minimum temperature of -40o C.The resistance for a single length of wire is 8.78 ohms per 1000 m at 20o C and8.96 ohms per 1000 m at 25o C. These resistance readings will double (17.56ohms or 17.92 ohms per 1000 m) for demolition applications where both apositive and a negative wire are necessary. Differences between these Figs and onsite measurements may be explained by:
a. actual length of demolition cable tested;
b. calibration of the ohmmeter/galvanometer used; and
c. environmental conditions.
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B-GL-361-008/FP-003 69
3-4-17. If normal demolition cable is not available, any twisted, two conductorcable between No 14 and No 22 gauge may be used. In an emergency, any strong,well insulated, two conductor, twisted cable may be used. The resistance of thecable will have to be determined in each particular case.
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70 B-GL-361-008/FP-003
SECTION 5MISCELLANEOUS EQUIPMENT
GENERAL
3-5-1. The placing of demolition charges frequently involves gaining access toawkward locations, fixing explosives where attachment is not easy, and creatingboreholes. To make the placement of charges easier, there are some standard toolsand equipment that can be employed.
CAMOUFLET SET, MK 1
3-5-2. The Camouflet Set, Mk 1 is a system used in the preparation ofcratering charges to create obstacles. Procedures for the use of the Camouflet Set,MK 1 is covered in Chapter 7. The complete set includes the following items:
Fig 3-5-1 Camouflet Set, MK 1
a. chisel, steel, weight 6.56 kg;
b. thumper, heavy, weight 22.68 kg;
c. clamp, tube withdrawing, weight 5.9 kg;
d. point, driving, quantity thirty (30), weight 1.08 kg;
e. key, ejector, weight 0.56 kg;
f. cap, driving, weight 2.04 kg;
g. adapter, weight 6 kg;
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B-GL-361-008/FP-003 71
h. stirrups, quantity four (4), weight 0.75 kg; and
j. tube, driving, quantity four (4), weight 19 kg.
3-5-3. As an additional accessory, wooden tamping rods are required. Thedimensions of these items are 3.66 m long and 0.349 to 0.381 m in diameter.These are painted white to seal the wood before initial use and are not to berepainted. The rods must be replaced when cracked, splayed, mushroomed, split orwhen it cannot be cleaned of explosive residue. All items, less the driving tubesand tamping rods are carried in a wooden box fitted with manila carrying handles.
DEMOLITION LADDER C2 AND SAFETY BELT
3-5-4. Demolition ladder.Special ladders and safety beltsassist access to bridge membersabove or below the deck. Althoughconventional ladders can be used,they are far from ideal. TheDemolition Ladder C2, is designedto be easily assembled by twopersonnel in variousconfigurations. It is constructed oflightweight aluminum weighing 36kg. The ladder consists ofinterconnected sections and
Fig 3-5-2 Demolition ladder C2
associated components, all capable of being stored compactly in or on an engineersection vehicle. It consists of the following six major components:
a. Hook Demolition Ladder. This is the top anchor assembly and ismade of solid aluminum. It will support a person and demolitionaccessories in a vertical position, unsupported at the base. It may beused in various configurations on the ladder:
(1) top end of ladder,
(2) top side of platform assembly, and
(3) on the extension, horizontally with the platform assembly.
b. Hoist Assembly. The hoist assembly may be placed between any twoladder assembly sections or at the very top of the ladder. It is used toassist in lifting explosives and accessories to the target area.
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72 B-GL-361-008/FP-003
c. Platform Assembly. The platform assembly may be placed anywherealong the ladder and is held in place by two transversal pins throughtwo alternate rungs. It may be used as an extension to the anchorassembly.
d. Ladder Section Assembly Base. Is 1.82 m long and is notinterchangeable with the upper sections. It is equipped with a footassembly designed to grip and hold onto hard surfaces such as steel,cement, or asphalt. The other end of the assembly is equipped with anice pick for gripping icy surfaces.
e. Ladder Section Assembly Upper. This consists of two identicalsections 1.82 m long which can be used in any order.
3-5-5. Safety belt. The safetybelt secures a soldier to a girder orladder, and includes a length ofcordage which can be used to liftitems.
Fig 3-5-3 Safety belt
ARMOURED ENGINEER VEHICLE (AEV)
3-5-6. The telescopic excavator arm of the AEV has a ladder fixed to thelower part of the boom. This can be used to gain access to structural members ona target. From the top of the AEV the ladder provides an additional reach of about3 m and is not extendable.
3-5-7. The AEV is also equipped with cutting and welding equipment whichcan be used to cut bridge members or reinforcement in concrete.
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B-GL-361-008/FP-003 73
Fig 3-5-4 AEV with Ladder
BOLT GUNS
3-5-8. Often the best location for a demolition charge is in an area thatprovides nothing to assist in the attachment of the charge. In this case, a bolt gunusing a powder cartridge, is able to attach fasteners to steel, concrete, or timber.There are various types of bolt guns available in field units. For moreinformation, see the user manual that is provided with the bolt gun.
3-5-9. General. The use, maintenance and safety procedures of engineerpower tools are described in B-GL-320-004/FP-001 and the applicable operatormanuals.
3-5-10. Compressor. A compressor and its variety of tools can be particularlyuseful in demolition tasks. Most compressors can be used for concrete breakingand drilling, and wood boring. Compressors may be hydraulic or pneumatic type.
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74 B-GL-361-008/FP-003
3-5-11. Pionjar. The Pionjar is the commercial name of a light weight,gasoline driven, combination breaker/drill that performs similar, but smaller tasksthan the compressor. It comes with a variety of tools and bits for variousapplications.
3-5-12. Hydraulic Tools. Engineer section vehicles are equipped withhydraulic power packs. Also available are portable hydraulic units (Stanley HP 1)or the trailer mounted hydraulic system. These units are equipped with a varietyof power tools which can be useful in demolition tasks if concrete drilling orwood boring is required. Hydraulic tool attachments, such as breakers, circularsaws and hammer drills are applicable to demolition tasks.
3-5-13. Power Augers. Power augers are available in engineer units. Anexample is the STIHL 4309 which can be fitted with a wood drill and a 17.2 cmcore drill.
3-5-14. The APC M113A2 and the MLVW SEV come fitted with ahydraulically powered auger. It comes with two sections of auger that are 20 cmin diameter and 1.5 m in length. See the operators manual or C-30-674-000/MS-002 for instructions on how to operate and maintain it.
BATTLEFIELD EFFECTS REMOTE FIRING SYSTEM (BERFS)
3-5-15. The BERFS system is a UHF radio link from a firing point to theexplosive / pyrotechnics. It eliminates the need for long lengths of demolitioncable and allows the easy control of elaborate battle simulation effects. A systemcomprises of one (1) transmitter and up to five(5) receivers. Each receiver caninitiate up to ten (10) circuits. Each circuit can be individually selected by thetransmitter and fired at any time and in any order. Typical operating range inopen terrain is 2 - 5 kms and in line of site conditions ranges of 10 - 25 kms can beexpected.
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B-GL-361-008/FP-003 75
3-5-16. Safety features built intothe BERFS system includetransmitters only being able toactivate receivers which belong tothe same system by the use of acoding system. Also, if thesituation occurs where two systemsare deployed operating on the samefrequency and are operated atexactly the same time, this will notresult in an unintentional firing of asystem. The firing command willbe ignored by one or morereceivers.
Fig 3-5-7 BERFS in transit case
Transmitters and receivers cannot be activated until the removable key has beeninserted into and activated the key switch. For detailed operating instructions seethe BERFS operators handbook.
3A-1. Ammonium Nitrate. Ammonium nitrate is the least sensitive ofexplosives, and requires a booster charge to initiate it. It is combined with a moresensitive explosive in many composite explosives. It is not suitable for cutting orbreaching charges because it has a low detonation velocity. However, because ofits excellent cratering effects and low cost, ammonium nitrate is used in mostcratering and ditching charges, and extensively in commercial quarryingoperations. Ammonium nitrate should be packed in an airtight container becauseit is extremely hydroscopic (absorbs humidity). Ammonium nitrate or compositeexplosives containing ammonium nitrate are not suitable for underwater useunless packed in waterproof containers or detonated immediately after placement.
3A-2. Pentaerythrite Tetranitrate (PETN). PETN is a highly sensitive andvery powerful military explosive. Its explosive potential is comparable to RDXand nitroglycerin. Boosters, detonating cord and some detonators contain PETN.It is also used in composite explosives with TNT or nitrocellulose. PETN is agood underwater explosive because it is almost totally insoluble in water.
3A-3. Cyclotrimethlenetrinitramine (RDX). RDX is another highlysensitive and very powerful explosive. It forms the base charge in the M6 electricdetonator. When RDX is desensitized, it serves as a booster, bursting charge ordemolition charge. It is used principally in composite explosives, such asComposition A, B, and C. RDX is available commercially as cyclonite.
3A-4. Trinitrololuene (TNT). TNT is the most common military explosiveworld wide. It may be in pressed or cast form, such as a booster, bursting anddemolition charge, or in a flake form. It can be used in combination with othertypes of explosives.
3A-5. Tetryl. Tetryl is an effective booster charge in its non-composite form,and as a bursting or demolition charge in composite forms. It is more sensitiveand powerful than TNT. However, RDX and PETN based explosives, which haveincreased power and shattering effects, are replacing tetryl and composite tetrylexplosives.
3A-6. Nitroglycerin. Nitroglycerin is one of the most powerful highexplosives and is comparable to RDX and PETN in explosive potential. It is theexplosive base for commercial dynamites. Nitroglycerine is highly sensitive andit is also extremely temperature-sensitive. Therefore it is not used in militaryexplosives.
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B-GL-361-008/FP-003 77
3A-7. Black Powder. Black powder is the oldest-known explosive andpropellant. It is a composite of 75% potassium or sodium nitrate, 10% charcoaland 15% sulfur. It is very sensitive to friction. Safety fuses, and some ignitersand detonators contain black powder.
3A-8. Amatol. Amatol is a mixture of ammonium nitrate and TNT. It is asubstitute for TNT in bursting charges. Some older Bangalore torpedoes use 80-20 amatol (80 percent ammonium nitrate and 20 percent TNT). Because itcontains ammonium nitrate, it is hygroscopic and must be kept in airtightcontainers. If properly packaged, amatol remains viable for long periods of timewith no change in sensitivity, power or stability.
3A-9. Composition A3. Composition A3 is a composite explosive containing91 percent RDX and 9 percent wax. The purpose of the wax is to coat,desensitize, and bind the RDX particles. Composition A3 is the booster charge insome newer shaped charges and Bangalore torpedoes.
3A-10. Composition B. Composition B is a composite explosive containingapproximately 60 percent RDX, 39 percent TNT, and 1 percent wax. It is moresensitive than TNT. Composition B is used as the main charge in shaped chargesbecause of its shattering power and high rate of detonation.
3A-11. Composition B4. Composition B4 contains 60 percent RDX, 39.5percent TNT, and 0.5 percent calcium silicate. Composition B4 is the maincharge in newer models of bangalore torpedoes and shaped charges.
3A-12. Composition C4 (C4). C4 is a composite explosive containing 91percent RDX and 9 percent non-explosive plasticizers. C4 has a high velocity ofdetonation and is waterproof. C4 is effective in temperatures between -56o C and76o C; however C4 loses its plasticity in colder temperatures. It is the primaryplastic explosive used in the Canadian Forces.
3A-13. Tetrytol. Tetrytol is a composite explosive containing approximately75 percent tetryl and 25 percent TNT. It is the explosive component in somemanufactured demolition charges. Booster charges require different mixtures oftetryl and TNT. Tetrytol is more powerful than its individual components, hasmore shattering power than TNT and is less sensitive than tetryl.
3A-14. Pentolite. Pentolite is a mixture of PETN and TNT. Because of itshigh power and detonating rate, a mixture of 50-50 pentolite (50 percent PETNand 50 percent TNT) is an effective booster charge in certain shaped charges.
3A-15. Dynamites. All dynamites contain nitroglycerin plus varyingcombinations of absorbents, oxidizers, antacids, and freezing-point depressants.Dynamites vary greatly in strength and sensitivity depending chiefly on the
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78 B-GL-361-008/FP-003
percentage of nitroglycerin. Dynamites are used for general blasting, includingland clearing, cratering, ditching and quarrying.
3A-16. Trigran. Trigran is a homogeneous mixture of 80% TNT and 20%atomized aluminum in the form of solid spherical particles of approximately 3 mmnominal diameter.
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B-GL-361-008/FP-003 79
ANNEX BMILITARY EXPLOSIVES LOGISTICAL DATA
3B-1. Figures 3B-1 to 3B-4 detail logistical data for common militaryexplosives packaging for planning purposes. The items listed here are availablethrough the supply system. Weights and dimensions listed are the largest packagedetails in reference. For more information refer to C-74-300-D01/TA-000.
3B-2. The following abbreviations are used in the tables:
MILITARY PLASTIC EXPLOSIVESSer Nomenclature NSN Packing
DetailsWeight
(kg)Dimensions (cm)
(a) (b) (c) (d) (e) (f)1 Chg Dml, Plastic
Comp C4, 1.25lb
1375-21- 850-0275
1 per wrap, 40 wrapsper wrbnd box
25.63 48.7 x 31.5 x150.5
2 Chg Dml, 8oz,PE, No 4
1375-99- 220-2413
1 per wax paperwrap, 10 wraps percrdbd box,4 box per wdn box
11.8 31 x 23 x 21
3 Chg, Dml,Plastic CompC4, M112, 1.25lb
1375-00- 724-7040
30 per wrap,1 wrap per wrbndbox
20.92 35.5 x 29 x21.8
4 Chg Ass, Dml,Mk138 Mod 1
1375-00- 834-7297
2 per wdn box 32.66 81.9 x 40.8 x46.9
5 Chg Dml,Detasheet, 0.083In (width), 38 ftroll
1375-01-.036-0443
2 rolls per fbrbd box 22.0 45 x 36.5 x21
6 Chg Dml,Detasheet, 0.125in, 25 ft roll
1375-01- 036-0444
2 rolls per fbrbd box 20.47 45 x 36.5 x21
7 Chg Dml, Detasheet, 0.42 In, 76 ft roll
1375-01- 038-6885
1 per fbrbd box 22 45 x 36.5 x 21
8 Chg Dml, Plastic DM12, 500 grams
1375-12- 120-7988
50 per wrap, 1 wrap per wdn box
30.30 49 x 29.5 x 24
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80 B-GL-361-008/FP-003
Ser Nomenclature NSN PackingDetails
Weight(kg)
Dimensions (cm)
(a) (b) (c) (d) (e) (f)9 Chg Dml,
Plastic Comp C4, 0.5 lb
1375-21- 112-7485
6 per bag, 9 bags per wdn box
18.7 45.1 x 24.8 x 260.7
Fig 3B-1 Military plastic explosives
SHAPED CHARGESSer Nomenclature NSN Packing
DetailsWeight(kg)
Dimensions(cm)
(a) (b) (c) (d) (e) (f)1 Chg Dml,
Shaped, M3A2, 40 lb
1375-00- 088-6691
1 per wdn box 29.54 52.6 x 29.7 x 34
2 Chg Dml, Shaped, M2A4, 15 lb
1375-00- 926-3939
3 per ctn, 1 ctn per wdn box
29.54 56.5 x 52.7 x 43.8
3 Chg Dml, Linear,
1375-21- 798-5886
Not available
4 Chg Dml,No 14, Mk 1, 11 lb
1375-99- 942-3314
5 per wdn box L20A1
74.39 81.6 x 35 x 32
5 Chg Dml, Necklace, L1A1
1375-99- 960-5409
1 per mtl box 74.5 122 x 101.6 x 77
Fig 3B-2 Shaped charges
MISCELLANEOUS MILITARY EXPLOSIVESSer Nomenclature NSN Packing
DetailsWeight
(kg)Dimensions
(cm)(a) (b) (c) (d) (e) (f)1 Tritonal
Granulated (Trigran)
1376-21- 884-8312
9 kg per ctnr, 4 ctnr per wrbnd box
48.9 92.5 x 27.6 x 37
2 Primer Detaprime
1375-21- 894-7614
240 per mtl box M2A1, 2 mtl box per wrbnd box
17.69 36.8 x 32.1 x 22.1
3 Dynamite, Forcite, 75%
1375-21- 861-8837
22.7kg per crdbrd box
Not available
4 Chg, Dml, CE/TNT, 0.875 lb
1375-21- 798-1610
As required Not available
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B-GL-361-008/FP-003 81
Fig 3B-3 Miscellaneous military explosives
MILITARY EXPLOSIVES ACCESSORIESSer Nomenclature NSN Packing
DetailsWeight
(kg)Dimensions
(cm)(a) (b) (c) (d) (e) (f)
1 Cap, Blasting Electric,No 12
1375-21- 116-6036
10 per can, 14 can per drum, 2 drum per wrbnd box
14.3 55.9 x 26.7 x 26
2 Cap, Blasting, Electric, C3
1375-21- 905-0092
10 per can, 14 cans per drum, 2 drums per wrbnd box
14.3 55.9 x 26.7x 26
3 Cap, Blasting, Electric, M6
1375-01- 192-9174
10 per crdbd ctn, 9 ctns per mtl can, 2 mtl cans per wdn box
16.59 41 x 44.5 x 29.5
4 Igniter, Time Fuse, Electric C2
1375-21- 898-7155
50 per ctn, 10 ctns per wdn box
11.5 48.9 x 30.5 x 20.9
5 Charge Explosive, Training, C2A1/2
1375-21- 858-1159
20 per can, 1 can per ctn, 12 ctns per fbr box
8.2 57.1 x 43 x 11.9
Fig 3B-4 Military explosive accessories
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82 B-GL-361-008/FP-003
ANNEX CCOMMERCIAL EXPLOSIVES AND ACCESSORIES
GENERAL
3C-1. Commercial explosives and accessories are used for applications suchas mining, quarrying and construction. The use of commercial explosive productswithin the Canadian Forces can be both cost effective and often necessary. Theymay be employed when service explosives are unavailable or insufficient for theimmediate tasks or when commercial products may be necessary because of theirspecial characteristics and lower cost.
3C-2. This annex is not intended to cover the entire realm of commercialexplosives and only deals with nitroglycerine and ammonium nitrate basedexplosives with some other types mentioned as primers and boosters. It isintended as a guide to be used in conjunction with: C-74-375-AAO/TA-000, C-09-011-001/AB-000 and B-CE-320-012/FP-004. Together with informationprovided by Ammunition Technicians and company representatives, theappropriate explosive products can be selected.
3C-3. Prior to the issue of commercial explosives to user units, the supportingammunition facility shall provide the user with a copy of the manufacturers'product brochure(s). The requirement for the explosives distributor to supplythese brochures shall be specified in the purchase order.
3C-4. Explosive selection is based on two primary criteria: the explosive willfunction efficiently and safely under the employment conditions, and is the mosteconomical product to produce the desired result. It must be determined whichexplosive (service or commercial) is best suited for the particular environment andhas the performance characteristics for the economic execution of the task.
CATEGORIES OF EXPLOSIVES
3C-5. There are basically two types of explosives.
a. Low Explosives. The chemical reaction of low explosives wheninitiated, is a form of combustion and occurs at a slow rate incomparison with high explosives. This process is called deflagration.The rate of deflagration varies between 400-700 m/s but can be as highas 1500 m/s depending on conditions such as confinement and pressure.An example of low explosives would be black powder or blastingpowder.
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b. High Explosives. In high explosives, the decomposition or chemicalreaction happens at a very fast rate. This process is called detonation.The velocity of detonation in high explosives is between 1000 - 8500m/s.
3C-6. When initiated, explosives are converted into gases with a hightemperature and tremendously increased volume. This causes energy to beexerted on the confining material. The effectiveness of explosives in blasting isdue to the speed with which this energy is produced. The released energy actsequally in all directions but naturally tends to escape through the path of leastresistance.
3C-7. For efficient blasting, the type and quantity of explosives used must becarefully considered. This annex deals with commerical high explosives as theyare more applicable to military requirements.
EXPLOSIVE DENSITY (SPECIFIC GRAVITY)
3C-8. Density is the most important characteristic when selecting anexplosive type. By knowing the explosive density, blasters can design effectiveand efficient shots of any size. All explosives have a density that is related to thedensity of water (1 gram per cubic centimetre). Density or Specific Gravity (SG)is the weight per measured unit, expressed as grams/cc compared to water.Explosive density determines the amount of explosive required in a specificborehole diameter, length of charge required and other charge criteria dependingon the application. Generally, the higher the density the more energetic theproduct.
EXPLOSIVE DENSITYSer Type Density (Specific gravity)(a) (b) (c)1 Granular Dynamite 0.8 - 1.42 Gelatin Dynamite 1.0 - 1.73 Cartridged Water Gelatin 1.1 - 1.74 Bulk Water Gelatin 1.1 - 1.35 Air Emplaced ANFO 0.8 - 1.06 Poured ANFO 0.8 - 0.857 Packaged ANFO 1.1 - 1.2
Fig 3C-1 Explosive Density
STRENGTH
3C-9. Density is sometimes also described as "stick count", which is theamount of cartridges required to fill a 50 lb box or case. For the dense gelatin
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84 B-GL-361-008/FP-003
explosives, it ranges from 104 to 155 cartridges, while the bulkier ammoniadynamite explosives range from 180 to 190 cartridges.
3C-10. It is important to be familiar with how the strength of commercialexplosives are measured when calculating charges. They can be measured in twoways: nitroglycerine comparison or measurement of energy.
3C-11. Nitroglycerine Comparison. For nitroglycerine based explosives, it isthe amount of nitroglycerine by weight in the explosive expressed as a percent.For other explosives, it is a strength measurement per unit of explosive comparedwith the same unit of straight nitroglycerine.
3C-12. Measurement of Energy. The terms in the following paragraphs arealso used in reference to the strength of an explosive product:
a. Absolute Weight Strength (AWS). The energy per unit of weightexpressed in calories per gram. It is the maximum theoretical explosiveenergy based on the ingredients in the explosive. The AWS of ANFOis 890 cal/g when mixed 94% ammonium nitrate to 6% fuel oil.
b. Absolute Bulk Strength (ABS). The energy per unit of volumeexpressed in calories per cubic centimetre (cm3). The ABS is equal tothe explosive's AWS multiplied by it's density. The ABS of ANFOequals 890 Cal/g x 0.85 g/cm3 or 756 cal/cm3.
c. Relative Bulk Strength (RBS). The bulk strength of the explosivecompared to ANFO. The RBS of an explosive is equal to the ABS ofthe explosive divided by the ABS of ANFO.
3C-13. Velocity of Detonation (VOD). The velocity of detonation is ameasurement of the speed, expressed in metres per second, at which a detonationwave travels through an explosive. It is influenced by pressure and containment,and generally the higher it is, the greater the shattering effect.
OTHER PHYSICAL CHARACTERISTICS
3C-14. Water Resistance. Commercial explosives vary widely in resistanceto water penetration. Straight nitroglycerine explosive and variants are the mostwater resistant. Ammonium nitrate based explosives have little water resistancebut can be packaged to provide moisture protection.
3C-15. Resistance to Freezing. Some explosives and blasting agents freezeand become difficult to work with. Gelatin explosives tend to stiffen and become
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firm after prolonged exposure to low temperatures. Ammonium nitrate basedexplosives may become set after absorbing moisture during storage andtemperature changes. It is sometimes desirable to keep explosives in a warmstorage area until use.
3C-16. Fumes. The detonation of explosives produces fumes, principally:carbon dioxide, nitrogen, water vapour, carbon monoxide and oxides of nitrogen,with the latter two being poisonous. Exposure to these fumes can be fatal. Anarea must be allowed to ventilate naturally or the fumes removed mechanically. Ifthis is not possible, a non-hazardous product shall be used. ANFO explosivesproduce more oxides of nitrogen than nitroglycerine based explosives and specialattention shall be paid to these fumes as they are particularly insidious. There aretwo types of fumes: permissible and non-permissible (above and below groundoperations). Guidelines for classification of fumes are found in the C.I.L.Blaster’s Handbook.
DANGERExplosive fumes may be poisonous and fatal. Ensure adequateventilation.
3C-17. Storage Qualities. Commercial explosives are all subject todeterioration. Humidity, temperature changes and poor storage facilities allowmoisture to be absorbed, which is the principle cause of deterioration. Moisturereduces sensitivity and strength, and may cause exudation of some ingredients.Nitroglycerine based explosives may exude nitroglycerine after prolonged orunsatisfactory storage conditions. Ammonium nitrate based explosives may notdetonate if too much moisture is absorbed. All explosives shall be physicallyinspected prior to use. Storage facilities should be dry, dark and have a constanttemperature. The oldest stock of explosives and accessories shall be used first,and only enough to complete the task should be removed from storage.
3C-18. Sensitivity. Sensitivity is a measure of an explosives propagatingability (ease of initiation by either heat, shock or friction). An explosive is either"cap sensitive" (sensitive enough to be initiated with a detonator or blasting cap)or a booster shall be used for initiation. This is important when deciding whereand how the charges will be initiated. All the accessories used shall becompatible.
NITROGLYCERINE BASED EXPLOSIVES (DYNAMITES)
3C-19. The physical characteristics of the various dynamites differ. Gelatindynamites are almost invariably plastic, while ammonia dynamites are quitegranular and possess no noticeable degree of cohesiveness. Semi-gelatins and
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straight dynamites have fair cohesiveness falling midway between gelatins andammonia dynamites in this respect.
3C-20. Warning: When handling nytroglycerine based explosives, do notallow the explosives to come into contact with bare skin. Ensure that the handlingarea is well ventilated. If nytrogrlicerine poisoning is suspected contact medicalauthorities immediately.
3C-21. Straight (Granular). The explosive base of straight dynamites isliquid nitroglycerine which is absorbed in a mixture of carbonaceous materialssuch as wood pulp, ground meal, etc. In straight dynamites the percentage ofnitroglycerine describes the grade. The relative high cost, sensitivity to shock andfriction, noxious fumes and very high flammability limits their use especiallysince the introduction of ammonia added dynamites.
3C-22. Ammonia Added. Ammonium-Granular dynamites are dynamites inwhich the primary source of energy is derived from the reaction of ammonium andsodium nitrates with various fuels. Nitroglycerine contributes to the explosiveenergy, but is primarily a sensitizer that ensures complete reaction of the nitratesand fuel mixture. In these dynamites, the ammonium nitrate with an explosiveenergy of about 70% that of nitroglycerine, is the primary energy source.
3C-23. Semi-gelatins. Semi-gelatin dynamites are ammonium dynamiteswhich contain a small amount of nitrocotton as a gelling agent and have higherpercentages of nitroglycerine than granular dynamites. There are no straight semi-gelatin dynamites. These products have better water resistance and a morecohesive, semi-gelatinous texture than granular dynamites. Semi-gelatinsgenerally have a slightly higher velocity of detonation than granular dynamiteswith equal strength markings.
3C-24. Gelatin Dynamites. Gelatin dynamites have as a base a water resistant"gel" made by dissolving nitrocotton in nitroglycerine. It is insoluble in water andtends to waterproof other ingredients with which it is mixed. At the same time, itbinds them together, rendering it cohesive and plastic in nature. There are twotypes of gelatin dynamites:
a. Straight Gelatin. Nitrocotton rather than an absorbent, combustablematerial is used to hold the nitroglycerine. It has too high a velocity ofdetonation for effective rock blasting and is expensive; and
b. Ammonia Gelatins. These differ from straight gelatins in that aportion of the strength is derived from ammonium nitrate. They are
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somewhat lower in velocity of detonation and slightly less waterresistant, but are more economical.
3C-25. Permissible Dynamites. Permissible dynamites are those which havebeen tested and approved for use in underground coal mines. They are ammoniadynamites, either granular or gelatins, which have a flame depressant additive,such as sodium chloride to reduce the volume, duration, and temperature of theexplosion's flame. They are designed to minimize the probability of a gas or dustignition. Permissible explosives absorb moisture readily and deteriorate as aresult. Storage and stock rotation must be carefully supervised.
3C-26. Dynamite Packaging. Dynamites are cartridged in some form ofwaxed or coated paper wrapping which prevents exudation of nitroglycerine andprotects the explosive from contact with outside objects, and in some instances,from moisture absorption. The outer dynamite wrappers shall never be removedfrom the cartridge other than for inspection or testing purposes by qualifiedAmmunition Technicians. The addition of dirt or grit to the raw explosives couldreduce sensitivity.
AMMONIUM NITRATE BASED EXPLOSIVES
3C-27. Ammonium Nitrate is an essential ingredient in nearly all commercialexplosives, including dynamites and water gels. It's predominant use is in theform of a prill with a particle density in the range of 1.40 to 1.50 g/cc. The maindifference between agricultural and blasting prills is that the blasting prills aregenerally less dense, more porous and have less antisetting coating than fertilizerprills. Ammonium nitrate prills with particle densities approaching the density ofsolid ammonium nitrate, over 1.7 g/cc are less sensitive to detonation.
3C-28. ANFO. The combination of 94 percent ammonium nitrate and 6percent (by weight) fuel oil produces an economical and effective explosive. Thevoids in the blasting prill enable the fuel oil to be retained by the prill in a uniformand intimate manner. They also improve the sensitivity by acting as sites for hightemperature "hot spots" or ignition points. If ANFO is to be used in wetconditions it shall be used in pre-packaged form and initiated as soon as possibleafter loading.
COMMERCIAL ACCESSORIES
3C-29. General. The following paragraphs describe various commercialaccessories. It is important to understand that manufacturers have differentmethods of making their products. It is imperative that both their users andsupervisors obtain the complete product description and become familiar with thisinformation before using the product.
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3C-30. Safety Fuse. Brands of safety fuse currently manufactured in Canadaare designed with similar characteristics as the military M700 time blasting fuse. Normally commercial safety fuse is black in colour vice green.
3C-31. Hot Wire Lighters. These devices in some respect resemble fire-works sparklers. They consist of a wire covered with an ignition composition thatburns slowly at a fairly uniform rate with an intensely hot ring of fire. They arelighted by a match and can be used to ignite a freshly cut length of safety fuse bymerely holding the burning portion of the lighter against it. Hot wire lighters arenot considered as timing devices.
3C-32. Thermalite Igniter Cord. This is a device for lighting safety fuse thatintroduces important principles of safety and efficiency when firing boreholes inrotation. It is cord-like in appearance and approximately 1.6 mm in diameter. Theactive composition is carried on a core of wire with an outer protective textile andwire counter-rings. The burning (actually an exothermic reaction) progresses at arelatively uniform rate along its length.
3C-33. Commercial Non-electric Blasting Caps. Non-electric blasting capsinitiate explosives when used with safety fuse and are normally manufactured intwo strengths, No. 6 and High Strength (H.S.). The caps come packaged incardboard cartons of 100 or in cases containing 1,000 or 5,000. A No. 8 strengthblasting cap is available by special demand.
3C-34. Comercial Electric Blasting Caps. They function instantaneouslywith the application of an electric current making it possible to fire multiple highexplosive charges simultaneously. They are manufactured in various strengthswith the most common being No. 6 and No. 8 strengths. The standard leg wirelengths and respective electrical resistances are found in C-09-011-001/AB-000.
3C-35. Delay Electric Blasting Caps. There are two different types: shortperiod and long period (LPV) delay.
a. Long Period Delay. These blasting caps have delay periods of justover ½ second in sixteen consecutive delays and are manufactured inNo. 8 strength. The length of the cap bodies varies with the delayperiod.
b. Short Period. These blasting caps have delay periods measured inmilli-seconds. The length of the blasting cap bodies varies dependingon delay period. The average timing chart can be found inC-09-011-001/AB-000. They are used mainly for surface blasting inquarries and construction work. The most notable advantages are:
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(1) reduced vibration and concussion,
(2) improved fragmentation,
(3) more predictable results with regard to the amount and directionof throw of the blasted material,
(4) backbreak and overbreak is reduced, with working faces left in animproved condition, and
(5) cut-off holes are minimized, with a reduction in the hazard ofunexploded dynamite.
3C-36. Specialty Blasting Caps. Non-Incentive (for underground coal miningoperations) Short Period Blasting Caps and Seismocap Electric Blasting Caps canbe used if nothing else is available. Refer to C-09-011-001/AB-000.
3C-37. Boosters. Boosters are tubular in shape and are composed of anintegral mixture of high explosive (PETN) and elastomeric binder. Thecomposition has both the appearance and some physical characteristics of rubber. They are compatible with electric and non-electric detonators, and detonatingcord. Key features of boosters are as follows:
a. Excellent moisture resistance.
b. Long shelf life. 3 to 5 years.
c. Excellent safety characteristics. Boosters are highly insensitive tomechanical impact, and there is no metal-to-metal contact between thebooster and blasting cap.
d. High energy performance. 8,000 m/s VOD with high brisanceoptimizes efficiency in priming ANFO and selected water gels.
e. Compact size. Minimizes both storage requirements and explosiveexposure in the blast area.
f. No fumes. A non-nitroglycerin priming and blasting system means thatusers are not exposed to hazardous fumes (i.e. no headaches as isassociated with nitroglycerin based products).
g. Easy handling. Primer units can be assembled or disassembled with a"twist of the wrist" requiring no punching for make up. This speeds uploading, both horizontally and vertically.
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3C-38. Detonating Cord (Primacord). The nomenclature differs with eachmanufacturer but basically it has all characteristics and uses as service detonatingcord. It is produced in rolls of 102 metres with standard properties detailed inC-09-011-001/AB-000.
3C-39. Detonating Relays. These devices are designed to accomplish shortinterval delay initiating of detonating cord. The explosives charges are similar tothose used in delay electric detonators. They have the same sensitivity to impactand should be protected from abuse. They consist of a 70 mm copper tube whichcontains explosive charges at each end, a delay element in between, andapproximately 305 mm of detonating cord crimped into the ends of the tube. Therelays can be spliced into the ring main or trunkline between charges and tiedusing a square knot, tape, stapling or clips. They are susceptible to moisture andshould not be used in wet conditions or underwater.
3C-40. Shock Tube Non-electric Detonating System. The shock tube non-electric detonating system is based on a hollow plastic tube that is lined with afinely powdered explosive composition, which when properly initiated,propagates a shock wave through the tube at a velocity of approximately 2000m/s. This shock wave initiates the primary charge (along with any delay element)in the detonator, which causes the main charge to detonate. The shock wave iscontained within the tube and has no effect on an explosive in contact with it.This allows this system to be used with any explosive regardless of sensitivity.This system is a sealed unit with the detonator securely crimped at one end and atthe other end a heat seal. The non-electric shock tube detonators come in variouslengths, for use with above and below ground and long and short delays. Thebest feature about this system is that the entire detonating system and all holes canbe initiated (i.e. made "hot" in commercial explosive terminology) before the firstcharge detonates, thereby reducing the chance of cut offs and misfires.
3C-41. Primers. Primers are small cylindrical charges of cap sensitive, highexplosive. They are available in various sizes for different applications,approximately 35 mm long and 32 mm in diameter, with holes running lengthwisethrough it for attachment to detonating cord or cavities for inserting detonators.
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ANNEX DIMPROVISED CHARGES
GENERAL
3D-1. Antitank Mines, shellsand bombs can be improvised asconcussion, buried or pressurecharges, and as the explosivecomponents of a booby trap. Theyare unsuitable as cutting chargeswhere close contact with the targetis essential.
3D-2. Mines. Whatever typeof antitank mine is used, there shallbe no attempt to initiate theexplosion
Fig 3D-1 Antitank mine prepared as animprovised charge
by using the mine’s fuse. The mine shall be prepared by packing the fuse cavitywith high explosive or by fixing a 0.5 Kg charge to the side of the mine oppositethe fuse cavity, armed by an initiation set detonated by initiating the charge.
3D-3. Shells. The explosive content of shells is small compared with theirtotal weight (even in high explosive shells, the explosive is only about 10% of thetotal weight). Generally speaking, only large calibre high explosives shells aresuitable. Small artillery and mortar projectiles are useful in booby traps due totheir fragmentation properties. To prepare a high explosive shell as an improvisedcharge, first carefully unscrew the fuse or shipping plug, preferably with a specialwrench made for this purpose. Never attempt to loosen the fuse or plug bystriking it with another object. The supplementary charge located there can beused as a booster. Place a small charge to initiate the booster. If this is notfeasible, another method is to fix one kg of high explosives as a cutting chargeagainst the thinnest part of the wall of the casing (about halfway between the baseand nose cap).
3D-4. Bombs. Unexploded bombs dropped from aircraft are unstable anddangerous and shall not be improvised as demolition charges. Unused generalpurpose or blast bombs from supply stocks contain the greatest proportion of highexplosives to total weight (about 50% in the case of 230 kg and 450 kg bombs)and are most suitable. They can be recognized by the parallel sides of the caseand comparatively snub nose. Armour piercing bombs have streamline cases andlong pointed noses, and are of little use for demolition purposes. General purposebombs can be armed using the following methods:
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a. if the fuse cavity (whichmay be located in thenose, side or tail)contains the standardbooster charge, but nofuse, place a smallcharge in the fuse cavityin close contact with thebooster charge; or
b. the main filling isusually reached from afiller cap under the tailcowling. Unscrew thefiller cap by steadypressure (never attemptto force it open)
Fig 3D-2 Arming bombs as demolitioncharges
and place a 0.5 kg charge in close contact with the main charge.
b. Danger. If a fuse is in the fuse cavity, do not attempt to initiate by anexternal charge over the fuse, use the method described.
IMPROVISED BANGALORE TORPEDOES
3D-5. Improvised bangaloretorpedoes can be prepared byplacing plastic explosive into a tubeor container such as:
a. metal pipe of 40 to 65mm diameter;
b. two 1.8 m angle ironpickets bound together;or
c. bamboo poles ofapproximately 50 mminternal diameter.
Fig 3D-3 Improvised Bangalore torpedo(1.8 m iron pickets)
3D-6. An example of an improvised bangalore torpedo using two 1.8 m angleiron pickets is illustrated in Fig 3D-3. The plastic explosive is armed withdetonating cord with double thumb knots no more than 1.5 m apart.
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IMPROVISED ANTIPERSONNEL PIPE CHARGE
3D-7 The improvised anti-personnel pipe charge is simplya short length of plastic or metalpipe enclosing plastic explosiveformed around detonating cordand pieces of metal. The piecesof metal are embedded in theoutside of the charge so that withthe frag-ments of the casing theyobtain the maximum energyfrom the detonation.
Fig 3D-4 Improvised antipersonnel pipecharge
IMPROVISED DIRECTIONAL MINE
3D-8. A directional mine (Fig 3D-5) can be improvised by packing about 4.5kg of explosives in the centre of a 180 or 225 litre oil drum. The drum is thenfilled with an assortment of rocks, gasoline in small containers and metal wire,nails and scrap.
Fig 3D-5 Improvised directional mine
3D-9. The device is exploded in front of approaching troops. For this reason,electric initiation or actuation by means of trip wire and a pull firing device isusually necessary. In open hilly country, oil drums similarly prepared but withabout 9 kg of explosive, can be rolled downhill to explode in the face of anadvancing force. Initiation of this type of charge is by a short length of safetyfuse.
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IMPROVISED SHAPED CHARGES
3D-10. The theory of shapedcharges is described in Chapter 3.Improvised shaped charges arefairly simple to prepare, the mainproblem being that of providing anappropriate charge container. Acan or wine bottle with a coneshaped bottom may be used for animpro-vised cone shaped charge(Fig 3D-6). The point of initiationmust be directly opposite the pointof the cone.
3D-11. The optimum depth ofcharge and the stand-off distancefrom the target are calculated asfollows:
a. charge depth is twice thedepth of the cone; and
Fig 3D-6 Improvised shaped charge
b. the stand-off distance (provided by a spacer or leg).
Stand-off = 3dDistance 2
where d = diameter of container
3D-12. The following methods may be used for cutting a glass bottle:
a. wrap a piece of string soaked in gasoline around the desired line of cut,light it on fire, and after 1-2 minutes, immerse the bottle in cold water;or
b. fill the bottle with oil to the level of cut, plunge a red hot poker into thebottle and lift off the neck.
PLATTER CHARGE
3D-13. The Platter Charge (Fig 3D-7) is the name given to a charge that relieson the Misnay-Schardin effect. This "plate" effect uses a mild steel plate withexplosive attached, and can penetrate up to 70 mm of steel at a distance of 90 m.The plate can be directed by careful moulding and charge initiation.
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Fig 3D-7 Platter charge
3D-14. The steel plate (preferably round, but square is satisfactory) weighingbetween 1 and 3 Kg is required. An equal weight of explosive is packeduniformly behind the plate and armed at the exact centre of the rear. A containeris an aid to aiming but is not essential.
3D-15. This charge can be used to destroy vital machinery parts such aselectrical gears and casings that might not be easily accessible. With practice, atarget the size of an oil drum can be hit at a distance of 20 m.
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APPENDIX 1AMMONIUM NITRATE AND FUEL OIL (ANFO)
GENERAL
3D1-1. ANFO (the explosive mixture of prilled ammonium nitrate and fuel oil)is the most common of the improvised explosives. It is widely used in industryand is either supplied commercially or manufactured locally. ANFO is cheap,very versatile and available world wide. It is suitable for demolition tasks such asroad and airfield construction and road cratering.
3D1-2. Only low density prilled (small ball) ammonium nitrate intended forexplosive applications with a particle density in the range of 1.40 to 1.50grams/cm3 shall be used in preparing ANFO. This type of ammonium nitrate hasa lower moisture content and uniform size, is relatively dust free, and hasexcellent fuel oil absorbency. It has good sensitivity to detonation by acting assites for high temperature "hot spots" or ignition points. All requests for thisgrade of ammonium nitrate shall be passed to a reputable explosives distributor toensure that the correct product is obtained.
3D1-3. Caution. Ammonium nitrate based fertilizers or powdered ammoniumnitrate shall not be used as alternatives. They are not designed for explosiveapplications and other ingredients may cause unsafe reactions when the fuel oil isadded or may produce undesirable results.
3D1-4. Ammonium nitrate readily absorbs moisture from the air which rendersit inert, so it must be protected from moisture. In wet ground, Trigran shall beused in place of ANFO, unless the precautions specified in paragraph 18 of thisAppendix are followed.
ADVANTAGES AND DISADVANTAGES
3D1-5. In comparison with other high explosives, ANFO has the followingadvantages:
a. it is economical;
b. it has a low velocity of detonation (2000 to 4750 m/s depending onconfinement) and produces high gas pressure, making it well suited as alifting charge;
c. it is free flowing, making it easy to pour into cratering chambers orvertical boreholes;
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d. prior to combining it with fuel oil, ammonium nitrate presents nosecurity problem, although it is subject to the same storage regulationsas the other high explosives and must be added to the net explosivequantity of the building or site; and
e. misfires in which the primer or booster has fully detonated, can bemade safe by adding large quantities of water.
3D1-6. In comparison with other explosives, ANFO has the followingdisadvantages:
a. ANFO has very poor water resistance. It readily absorbs moisture fromthe air and must be stored in airtight containers or used the same day itis mixed. Dampness will cause the prills to clog together or breakdown into crystals;
b. it has low sensitivity and therefore another high explosive is required asa booster;
c. it gives off no toxic fumes prior to detonation, but on detonation itproduces extremely toxic gases which must not be inhaled;
d. the production of ANFO is time and labour intensive and requiresknowledgable supervision;
e. diesel fuel oil is a skin irritant;
f. it will burn and may explode if the mass is sufficient; and
g. the ammonium nitrate will react with copper, tin, bronze or brass,giving off toxic and inflammable fumes.
PREPARATION OF ANFO
3D1-7. General. Although ANFO will function without precise measurement,the most efficient results will be achieved with accurate measurement. Forplanning purposes the mixture ratio is 94% ammonium nitrate to 6% fuel oil. Themeasurement for the mixing of the components of ANFO can be carried out bytwo methods: by weight or by volume.
3D1-8. Volume Measurement. A calculated volume of fuel oil is added to aknown volume of prilled ammonium nitrate (PAN). It is necessary to know thespecific gravity (SG) of both the prilled ammonium nitrate and the fuel oil must beknown. The SG of fuel oil is reasonably constant and for our purposes 0.8 is used(1 litre of fuel oil weighs 0.8 kg). The SG of PAN varies according to its countryof origin and must be determined (from indications on the packaging or from the
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producer). The amount of fuel oil that is mixed with a known volume of PANaccording to the SG is in the table below.
Ser PANSG
PAN(units) to one unit fuel oil
(a) (b) (c)1 0.8 162 0.9 153 1.0 14
Fig 3D1-1 Ratio of PAN to fuel oil according to SG
3D1-9. Weight Measurement. To mix ANFO by weight, it is necessary toknow the weight of PAN to be used. The best mixing ratio of PAN to fuel oil is16.86 : 1 (for example, 1 kg of fuel oil to 16.86 kg of PAN).
3D1-10. Fig 3D1-2 shows the amount of fuel oil required for a known weight ofPAN. Fig 3D1-3 shows the equivalent volume of fuel oil required to mix with aknown weight of prilled ammonium nitrate.
Volume of fuel oil required ( )Ser Volumeof PAN CA & US PAN
10 100 6.0 7.4Fig 3D1-3 Weight Measurement (Using PAN with a SG of 0.8 gm/cm3)
MIXING
3D1-11. In Canadian Forces applications, the volume of ANFO seldom warrantsthe use of a specially designed industrial mixer. Mixing is normally done by handor concrete mixer.
3D1-12. When using a concrete mixer, the following safety rules are to beobserved:
a. the mixer shall be grounded and fully inspected to ensure serviceabilityand safety prior to use;
b. only electric, diesel or compressed air driven mixers are to used sinceANFO is flammable; and
c. if the mixer is used at irregular intervals, the mixing cowl shall becoated with an epoxy such as fibreglass to prevent corrosion of themetal by ammonium nitrate.
3D1-13. When ANFO is mixed by hand, the following procedure isrecommended:
a. pour the required quantity of PAN into the mixing container;
b. pour the required quantity of fuel oil into another container and mix in ameasured quantity of soluble dye. "Waxoline" red dye at 1:2000 givesa satisfactory result;
c. pour the dyed fuel oil slowly into the PAN and mix until the wholemixture is a uniform colour (approximately two minutes);
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d. after mixing, it is recommended to store the ANFO in a non-absorbentcontainer for approximately one hour to allow the fuel oil to penetratethe prills; and
e. detonate the ANFO as soon as possible after loading it.
3D1-14. Useful items for mixing small quantities of ANFO are available fromunit resources, including:
a. polyethylene containers:
(1) one litre jug for measuring fuel oil,
(2) a bucket graduated in litres for measuring PAN,
(3) 30 litre garbage can for mixing ANFO, and
(4) a funnel for pouring ANFO;
b. rubber gloves;
c. wooden paddles; and
d. safety goggles.
3D1-15. When large charges arerequired, it may be more convenientto prepare mixes in increments of 40kg (normally one bag). The con-tents of a bag may be poured into awooden mixing tray and mixed withwooden paddles.
LOADING
3D1-16. ANFO can be loadedmechanically or by hand. For most
Fig 3D1-4 Timber mixing trough
military tasks, hand loading of the charge will be the only method available. It isnot the most efficient method but it is simple and gives satisfactory results.
DANGER. Ensure the borehole or chamber has cooled sufficiently prior to loading ANFO.
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3D1-17. ANFO shall not be poured into wet holes. Water contamination ofANFO, which leads to poor fragmentation or even misfires, can be detected by theyellow or reddish-yellow fumes of oxides of nitrogen formed on detonation.Three methods of overcoming this problem are:
a. use another type of explosive which does not react with water (forexample, Trigran);
b. remove water from the chamber (blown out with compressed air); and
c. place ANFO into sealed plastic bags of the required size.
PREPARING ANFO
3D1-18. A booster charge shall be used to initiate ANFO. In most militaryapplications this will be C4 plastic explosive. The total quantity of C4 requiredfor the booster charge is normally a ½ block of C4. The size of the chambercharge is determined by soil type as described in Chapter 6.
3D1-19. In a borehole or cratering application, the following procedure is used:
a. after allowing the borehole or the chamber to cool, pour half of themain charge into the chamber;
b. lower the booster charge down the borehole or the camouflet tube. Ifthe charge sticks to the sides of the borehole or driving tube, gentlypush with the authorized wooden tamping rod. Never apply undueforce or pound on the booster charge.
c. load the remaining ANFO into the hole, periodically run the tampingrod into the hole to ensure even distribution; and
d. when the main charge has been completely loaded, stem the hole withearth or drill cuttings. This will provide short term protection to keepmoisture out.
CLEANING OF EQUIPMENT
3D1-20. Items manufactured from copper, tin, brass or bronze are not to be usedin operations involving ammonium nitrate. If they do come in contact withammonium nitrate compositions, they are to be washed immediately with soapand water.
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3D1-21. Implements, troughs, tamping rods and containers used for thepreparation and placement of ANFO are to be washed with soap and water as soonas possible after use. Cleaning will take place on the Demolition Range or thetask site.
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CHAPTER 4ELECTRICAL PROCEDURES
SECTION 1SAFETY
GENERAL
4-1-1. This chapter describes the following:
a. firing circuits;
b. electrical, dual and combination initiation;
c. electrical hazards; and
d. safety procedures.
4-1-2. Safety regulations, responsibilities and procedures for generaldemolition use and training are covered in B-GL-304-003/TS-OA1,B-GL-320-009/FP-001 and range standing orders. This manual complementsthese publications and shall be used in conjunction with these publications.
STORAGE AND TRANSPORTATION
4-1-3. The safety regulations governing the storage and transportation ofexplosives are outlined in B-GL-304-003/TS-OA1, and pertinent extracts areincluded in B-GL-320-009/FP-001.
NON-ELECTRIC INITIATION
4-1-4. The safety precautions and procedures for basic charges and non-electric initiation are described in B-GL-320-009/FP-001.
SAFETY DISTANCES
4-1-5. B-GL-320-009/FP-001 details the requirements for safety distancesduring operations and peacetime training. These safety distances are repeated inAnnexes A and B to this chapter.
ELECTRICAL INDUCTION HAZARDS
4-1-6. Electrical firing circuits can be fired prematurely by electric currentinduced by electromagnetic waves emitted by radio transmitters, radars, andelectrical machinery. The danger of accidental firing occurs when a circuit, or aportion of a circuit, acts as an aerial and picks up energy from a source. This
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danger is greatest when part of the circuit, through coincidence or accident, is ofthe correct length and configuration to become resonant to the frequency of thesource. This danger may be reduced by observing the safety precautions in thefollowing paragraphs.
4-1-7. Electric detonators and igniters.
a. users shall ground themselves for ten seconds prior to handling electricdetonators or igniters;
b. electric detonators and igniters shall be kept in service packs or inclosed metal containers until connected into circuits. Do not open in anaircraft or vehicle, or within 30 m of a radio set;
c. leads shall be twisted together, with only the minimum length untwistedand separated to make the connection; and
d. connections between electric detonator leads and demolition cable shallbe secured with tape.
4-1-8. Demolition cable.
a. only tightly twisted cable is to be used. Knotted or cable with loops init shall not be used;
b. the bare ends of the cable at the blasting machine shall be shorted byshunting (twisting together) and grounded when connecting electricdetonator leads to the other end;
c. firing cable shall be kept away from power and telephone cables;
d. electrical tool cables shall be cleared from the site before electricdetonators are connected;
e. the demolition cable shall, whenever possible, be buried, or at least laidflat on the ground; and
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f. if two pieces of demolition cable are joined, Fig 4-1-1 illustrates therecommended method.
Fig 4-1-1 Joints in demolition cable
4-1-9. The electrical induction hazard may be reduced further by avoiding thefollowing circuit configurations:
a. single cable series circuits;
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106 B-GL-361-008/FP-003
b. detonators connected to the same strand of a double cable, in multipledetonator or igniter electric applications (the fewer detonators thebetter); and
c. a detonator on a circuit being held by a person who may act as anaerial.
4-1-10. Demolition circuits shall only use one electric detonator wherepossible. The only electrical accessories which shall be used are a blastingmachine, a length of twin twisted demolition cable, and an electrical detonator origniter electric. When using electrical initiation, a back-up, non-electric methodof initiation shall also be used, i.e. combination initiation.
4-1-11. Firing circuits using several detonators, or igniters electric may benecessary in Battle Noise Simulation. In this case, the safety distances in Fig 4-1-2 shall be observed to reduce the electrical induction hazard.
Safety distanceSer Item Field
radioField radar
(a) (b) (c) (d)1 Electric detonator or igniters
electric in sealed packsNo
hazardNo hazard
2 When twisting the leads ofelectric detonator or igniterelectric or when connectingmulti-detonators circuits
40 m Locating mortar-70 mInfantry patrol - 2 m
3 When connecting an electric detonator origniter electric into a single detonatorcircuit
30 m Artillery- 100 mInfantry patrol - 2 m
4 Assembled single detonator or singleigniter electric circuit with a minimumlength of demolition cable of 50 m
1 m Artillery- 100 mInfantry patrol - 2 m
5 Assembled multi-detonator origniter electric circuit
If the effect of a premature firing is critical,safety distances as in serial 2 must befollowed.
Fig 4-1-2 Safety distances for field radio and radar equipment
4-1-12. Distances at which military mobile radio and field radar equipment donot affect electric detonators or igniters electric in the course of preparation and incompleted circuits are given in Fig 4-1-2. Safety distances from civilian radio,television, and radar transmitters are given in Fig 4-1-3.
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4-1-13. Helicopters may not fly over or land within 30 m of an electrical firingcircuit.
NOTE When the transmission is a pulsed or pulsed continuouswave type and its pulse width is less than 10 micro seconds, thepower indicated is average power. For all other transmissions thepower indicated is peak power.Fig 4-1-3 Safety Distances from civilian radio, television or radar transmitters
4-1-14. Lightning strikes or near misses may initiate both electrical and non-electrical firing circuits. Therefore all blasting activities shall be suspendedduring electrical storms or when one is approaching.
4-1-15. Electric initiation shall not be used within 150 m of an energized powerline. Use non-electric initiation or de-energize the power line.
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SECTION 2FIRING CIRCUITS
TYPES OF FIRING CIRCUITS
4-2-1. In military demolitions, a firing circuit consists of detonating cord linesand a firing system or initiation set and is designed to initiate multiple chargessimultaneously. They can be very simple as in a trunkline, or as the situationdictates, they can be more elaborate in design consisting of double horizontal andvertical ring mains. Initiation can be by electrical or non-electrical means or byboth means. The four methods of joining multiple charges for simultaneousinitiation are: trunkline, ring main, simple firing circuit, and maximum firingcircuit. The choice is dependent on the importance and complexity of the target,time available and on the tactical situation.
4-2-2. Trunkline. A trunkline is a simple length of detonating cord withmultiple charges located along either side and normally initiated at one end only.Trunklines are employed on simple demolition tasks of little tactical importance.
Fig 4-2-1 Trunkline
4-2-3. Ring Main. The ring main doubles the number of ways the attachedcharges can be initiated. The ring main is configured so the detonation wave willtravel from two directions vice one, as in the case of a trunkline fired with oneinitiation set. It is preferable to initiate the ring main at two points, kept wellapart, so if one initiation set fails, the other will still initiate the charges. Whentwo initiation points are used, the ring main shall be closed using a cross-over (apiece of detonating cord, minimum 2 m in length). It is connected between the
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initiation sets and the first charges at both ends, to ensure that the detonating wavetravels to all charges from both directions.
Fig 4-2-2 Ring main
4-2-4. Vertical Ring Main. Vertical ring mains are configured around thetarget in a vertical plane to connect multiple charges located in one area of a targetfor simultaneous initiation (i.e. all the charges required for one cut of a bridgespan).
4-2-5. Horizontal Ring Main. A horizontal ring main is configured around atarget in a horizontal plane and all vertical ring mains are connected to it.
4-2-6. Simple Firing Circuit. A simple firing circuit is generally employedon complex targets where a second attempt at initiation is possible in the event thefirst attempt was unsuccessful. Most preliminary demolition targets requiresimple firing circuits. A simple firing circuits consists of a horizontal ring mainwith single vertical ring mains as required. Each charge is connected to a verticalring main by a single detonating cord lead. Initiation points are located on thehorizontal ring main.
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110 B-GL-361-008/FP-003
Fig 4-2-3 Simple firing circuit
4-2-7. Maximum Firing Circuit. A maximum firing circuit reduces the riskof failure by doubling the vertical and horizontal ring mains, by doubling thedetonating cord leads to charges, and by doubling the number of initiation points.Normally, maximum firing circuits shall be used on all reserved demolitions, andin situations where there is doubt about a second chance of firing in case of afailed first attempt. Such thorough precautions are warranted because a reserveddemolition cannot be allowed to fail. The two detonating cord leads from eachcharge are connected to different vertical ring mains. The horizontal and verticalring mains are connected in all possible locations.
Fig 4-2-4 Maximum firing circuit
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INITIATION METHODS
4-2-8. Single Initiation. Initiation of a firing circuit by one initiation set,either electric or non-electric. It is only normally used on a trunkline.
4-2-9. Dual Initiation. Initiation of a firing circuit with two independent butsimilar methods, either two electric initiation sets or two non-electric initiationsets.
4-2-10. Combination Initiation. Initiation of a firing circuit with both types ofinitiation, electric and non-electric, operating independently of each other.
PROTECTION OF FIRING CIRCUITS AND CHARGES
4-2-11. Every effort shall be made to protect firing circuits and charges. Themost obvious threat is direct and indirect fire. However, weather, vibration andsabotage shall also be considered. Protective measures will be thorough and thefiring circuit and charges shall be inspected regularly on long standingdemolitions.
4-2-12. Enemy Fire. Where possible, firing circuits and charges shall belocated on inside surfaces, away from possible observation. This will lessen thechance of damage from direct fire. Demolition cable shall be buried whenpossible.
4-2-13. Weather. Although current explosives and accessories are designed towithstand dampness, long standing charges and firing circuits shall be protectedfrom the weather. Charges will be covered with moisture proof material.Detonating cord will have shallow "U"s bent into it, as close to the initiation pointand charges as possible to allow water to drip off and not contaminate theexplosive. Safety fuse will not be prepared until just prior to use, and then keptdry until State 2 is ordered. Initiation sets will be protected against rain, dew, andmoisture.
4-2-14. Heat. Firing circuits and charges must be protected from direct sunrays. Plastic explosives tends to deteriorate at temperatures above 60oC, anddetonators become more sensitive. In very hot climates, the charges and firingcircuits shall be placed on the shady side of the targets, and the metal targetsshaded, if possible.
4-2-15. Vibrations. Vibration caused by traffic, direct and indirect fire, orwind may loosen charges and connections in firing circuits. Charges shall befixed to targets by bolt guns and appropriate fasteners. If this is not possible, theywill be held in place with wire and wood or strapping devices. Firing circuits willbe protected from traffic damage by the use of sandbags or timber. Loose lengths
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will be tied back from roadways and tied at intervals to protect against fraying andthe possibility of pulling out from charges or detonators. Initiation points must beat least five metres apart to prevent both being damaged by a single blast.
4-2-16. Pedestrians. Large numbers of refugees can be expected to crossreserved demolition targets. Charges and firing circuits may be tampered withinnocently or deliberately. Proper refugee control, including signs, escorts anddesignated routes are the best methods of prevention.
4-2-17. Inspections. Regular inspections and testing of long standing charges,firing circuits, and protective measures are essential to prevent failures andproblems. Points to look for include:
a. moisture penetrating initiation points and charges;
b. fraying of cable and coatings on wire and detonating cord;
c. undue strain on cable and detonating cord; and
d. loose charges and fixtures.
4-2-18. Important. Non-electric initiation sets and detonators of either typeare never buried so they may be inspected during maintenance or in the event of amisfire.
4-2-19. Effects of Nuclear Explosions. If a nuclear explosion is possible, thefollowing considerations and counter measures are recommended:
a. Blast. Charges and firing circuits shall be fixed to targets as securelyas possible, by the use of bolt guns or banding equipment;
b. Heat. Heat may explode detonators, ignite charges and detonatingcord, and burn insulation on demolition cable. They shall be protectedby shielding with items that provide thermal protection such ascorrugated galvanized iron (CGI), steel pickets and sand bags. Thesestores will be kept on hand to replace any damaged items; and
c. Electro-Magnetic Pulse. EMP from a nuclear blast can create anelectrical induction hazard. The only practical counter measure is todelay changing to state 2 until the last possible moment, as well asfollowing the guidelines discussed earlier.
4-2-20. When using electrical initiation, armoured vehicles shall not be used asfiring points due to electrical induction hazards unless:
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a. there is a minimum of 50 m of demolition cable between the blastingmachine and the nearest detonator; and
b. all other radio frequency/induction safety precautions are compliedwith.
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SECTION 3ELECTRICAL INITIATION
GENERAL
4-3-1. Electrical initiation has the following advantages over non-electricinitiation:
a. the electrical circuit can be tested for continuity until the last moment;
b. positive control of the demolition is maintained until it is initiated; and
c. if time is a critical factor, the demolition can be initiated at any givenmoment from a place of safety.
4-3-2. When electrical induction factors are considered, electrical initiationmay have to be rejected in favour of non-electric initiation. Prior to the start ofoperations, all electrical initiating equipment shall be checked as per Chapter 3before any tests are conducted. Prior to the start of demolitions, site commanderswill ensure that they are in possession of all blasting machine crank handles.
DEMOLITION CABLE TESTING
4-3-3. Test Demolition Cable. All personnel working with electricalinitiation shall know the procedures and hand signals involved. The tests arecontrolled by the person at the firing point, with an assistant at the other end of thecable. When a signal is sent or answered the person signalling will stand erectwith feet slightly apart. The signal shall be given clearly so it can be easilyunderstood. The following procedure and signals are used:
a. Open Circuit. The tester starts by holding both ends of the demolitioncable apart and above his shoulders, clearly indicating separation of thetwo conductors. The assistant separates the conductors, holds one ineach hand and returns the "open circuit" signal as shown in Fig 4-3-1.The tester now untwists the ends of the conductors and inserts theminto the ohmmeter tester, which must read fault.
b. Closed Circuit. After completing the open circuit test, the testersignals by holding the arms above the head and bending the elbows sothe hands touch, clearly indicating a closed circuit. The assistant twiststhe two bare ends of the conductors together and returns the "closedcircuit" signal to the tester as shown in Fig 4-3-2. The tester now takesa reading which should show continuity and the number of ohms
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resistance. The resistance reading of the wire and the combinedresistance of all electrical detonators shall not exceed the capacity ofthe blasting machine.
Fig 4-3-1 Open circuit signal Fig 4-3-2 Closed circuit signal
c. Shunt and Ground. Upon completion of a successful test, the testertwists the bare ends of the conductors together and grounds them byinserting 2-3 cm into the ground. The tester then signals to the assistantby holding one arm straight above the head, making a clear circularmotion then bending and pointing to the ground as shown in Fig 4-3-3.The assistant returns the signal and completes shunting and grounding.
Fig 4-3-3 Shunt and ground signal4-3-4. Fault Finding. If the tests indicate no continuity, there are one or morefaults are in the cable. The following procedure will indicate where the fault islocated:
a. the tester untwists the conductors so the circuit is open, while ensuringthe conductors are twisted together at the assistant's end;
b. starting at the middle of the cable, using the ohmmeter tester andpricker cables determine what end of the cable has the break. Keep
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going to the half way point, determining which half has the break.When the tester reads "Fault" or "discontinuity", the break is locatedbetween the last test location and the present location; and
c. the break or problem is then repaired as in Figure 4-1-1 and thecontinuity of the cable is checked again.
4-3-5. Discontinuity. After a successful demolition, the cable shall be testedfor discontinuity. This will confirm that there are no shorts or groundingoccurring in the cable.
TESTING ELECTRIC DETONATORS
4-3-6. This test shall be conducted by the soldier firing the demolition, and itshall be supervised by an NCO. The electric detonators are tested one at a timeusing the following procedures:
a. move the electric detonators from the ammunition point to a safe area20 m from personnel and 8 m from other explosives or accessories);
b. remove helmets if worn;
c. personnel conducting the test will ground themselves for ten seconds;
d. carefully remove an electric detonator from the container;
e. straighten the leg wires and under control, place the electric detonatorunder a helmet or sandbag;
f. with all personnel kneeling and keeping their backs to the electricdetonator, remove the protective cover from the leg wire ends. Attachthe wire ends to the terminals on the ohmmeter tester, note the amountof resistance;
g. if satisfied with test, twist the leg wire ends together and stick the endsinto the soil to ensure grounding;
h. if not satisfied with results of the test, return the defective electricdetonator to the Ammunition NCO for marking and disposal;
j. under control, remove the electric detonator from under the helmet orsandbag, and coil up the leg wires while moving towards the leg wireends stuck in the ground; and
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k. the tested electric detonator is either used immediately or is storedunder a helmet or sandbag in a designated area under supervision.
ELECTRICAL CIRCUIT TESTING
4-3-7. The following applies if the electric detonator has not been usedimmediately after testing and has been temporarily stored or placed down:
a. personnel connecting electric detonators to the demolition cable shallfirst ground themselves for ten seconds prior to handling electricdetonators; and
b. the demolition cable shall be grounded prior to and upon completion ofconnecting the electric detonator (at the firing point end onceconnected).
4-3-8. Once the electric detonator is connected to the demolition cable, thecircuit shall be tested for continuity and resistance. Normally this is done lastwhen all other activity on the demolition site is complete and unnecessarypersonnel are off the site. This test shall be done on a regular basis on longstanding demolition charges as part of regular maintenance. The procedure is asfollows:
a. ensure the electric detonator is in a safe area 20 m from personnel and 8m from other explosives and accessories and covered with a helmet orsandbag;
b. personnel ground themselves, then the ends of the demolition cablelocated at the firing point are removed from the ground. The ends areuntwisted and connected to the terminals of the ohmmeter tester. Therewill be continuity and the resistance will not exceed the capacity of theblasting machine; and
c. the ends of the demolition cable are then twisted together and stuck intothe soil for grounding.
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Fig 4-3-4 Connecting an electric detonator to demolition cablein a single detonator firing circuit
CALCULATE POWER REQUIREMENTS FOR SERIES CIRCUITS
4-3-9. General. For most military demolition operations, the present blastingmachines are sufficient and power requirement is not a consideration. Otherfrequently used power sources such as batteries and generators have varyingcapabilities. In the case of multi-detonator circuits with demolition cable lengthsof over one km, as in Battle Noise Simulation, it is important to know the totalcircuit resistance and power requirements. For military applications series circuitsare used because of the limited numbers of detonators or igniters electric used.For information on series in parallel or parallel circuits see C-09-011-001/AB-000.
4-3-10. Resistance. It is necessary to determine resistance to ensure that thepower source is adequate to fire all electric detonators or igniters electricconnected to the firing circuit. The total resistance in a series circuit is the sum ofall the detonators or igniters electric, extension wires (if used) and demolitioncable. Once the total resistance is known, the power required (in voltage) can becalculated using the Ohms Law.
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4-3-11. Ohm’s Law. Ohms law is used to calculate the electromotive forcerequired in volts to detonate the electric detonators or igniters electric on a circuitfor which the resistance is known.
E = IRWhere: E = electromotive force (volts) I = current (amps) R = total circuit resistance(ohms)
4-3-12. Electric Power Formula. The power required can be calculated inwatts or converted to watts if a known power source has an output expressed inwatts.
W = IEor
W = I2R
Where: W = electric power required (watts) I = current (amps) E = electromotive force (volts) R = total circuit resistance (ohms)
4-3-13. Planning. The amperage required for a circuit containing one or moreelectric detonators or igniters electric, connected in series will always be 1.5 amps,therefore "I" will always be 1.5 amps in the calculations. For planning purposes,when using military electric detonators or igniters electric, use two ohmsresistance per electric detonator or igniter electric. Fig 4-3-5 can be used tocalculate the resistance of the most common sizes of copper wire. If any othertype of wire is used, the resistance of that wire must be known before resistancecalculations are done. Resistance calculations are for planning purposes and arenot intended to replace continuity and resistance checks.
4-3-14. Power Source Output. In any electric firing circuit, the power sourcemust exceed the power required. To provide a margin of error for old powersources or inaccurate readings, the calculated electric power requirement of acircuit shall never exceed 90% of the power source. This information is availablefrom the nameplate on the source or can be measured with a volt meter.
Note: Normal military issue. Fig 4-3-5 Resistance of Copper Wire
4-3-15. Sample Calculations. The following sample calculations are shown toillustrate how the resistance of a circuit is to be calculated to determine if it iswithin the capabilities of the blasting machine. The circuit will be comprised ofsix igniters electric, 2 m leg wire extensions of 16 gauge wire and 900 m of 14gauge demolition cable.
a. Step 1. Calculate resistance of Igniters electric. 6 x 2 ohms = 12 ohms
b. Step 2. Calculate resistance of demolition cable (two strands). (2 x 900 m) x 2.525 ohms (from Fig 4-3-5)
305 m = 14.9 ohms
c. Step 3. Calculate resistance of extension wires. (6 igniters electric x 2 leg wires x 2 m extension wires) x 4.02 ohms (from Fig 4-3-5)
305 m= 6 x 2 x 2m x 4.02ohms
305m= 0.316 ohms
d. Step 4. Calculate total resistance.
(1) Igniters electric = 12 ohms
(2) Demolition cable = 14.9 ohms
(3) Extension wires = 0.316 ohms
(4) Total circuit = 27.216 ohms, which is within the capabilitiesof the blasting machine
CONNECTING SEVERAL DETONATORS TO DEMOLITION CABLE
4-3-16. For series type circuits, the preferred method for military applications,all the electric detonators or igniters electric are connected together to provide a
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single path for the current. One leg wire of one detonator is connected to a legwire from the next detonator, and so on until all detonators or igniters electric areincluded in the circuit. If the leg wires are not long enough, then leg wires may beextended by the use of single conductor wires of approximately the same wiregauge. It is important that these extension wires be taken into account whencalculating circuit resistance.
Fig 4-3-6 Connecting lead wires in a multi-detonator firing circuit
ELECTRIC INITIATION SEQUENCE
4-3-17. Before Firing. The following procedure will be employed when usingelectric initiation:
a. prepare charges, then the ring main(s);
b. under supervision, test the electrical initiation components, then theentire electric initiation system (can be completed concurrently withother tasks);
c. the designated person in charge shall ensure that all unnecessarypersonnel, stores, equipment and vehicles have cleared the danger areaor are under protective cover;
d. inform any sentries and other units in area that firing is about tocommence; and
e. upon command of the authorized person, the electric detonator can betaped to the cradle on the ring main to complete the firing circuit. Bothends of the body of the electric detonator shall be left exposed so theycan be seen in the event of a misfire.
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Fig 4-3-7 Connecting detonators to demolition cable in multi-detonator firingcircuit
4-3-18. Firing. When using electric initiation the following procedure is used:
a. all remaining personnel (the firing party) move to the firing point;
b. the intention to fire is signalled by use of voice (shout "firing" in thefour directions), whistle or air horn (12 short blasts with one secondintervals);
c. during a minimum pause of ten seconds, personnel listen for sentriesand watch for unauthorized personnel;
d. the firing party will ground themselves, and continuity is verifiedagain;
e. the demolition cable is connected to the previously tested blastingmachine and the crank handle is given to the person designated to firethe demolition;
f. upon the command of the authorized person in charge, the demolition isfired; and
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g. if successful, discontinuity is verified and the demolition cable ends areshunted and grounded. If unsuccessful, a second firing is immediatelyattempted.
4-3-19. When the demolition is fired all personnel will wear helmets, unlessthey are in prepared bunkers or shelters, or are outside the danger area. Allpersonnel will be alert for flying debris, and observe or listen for possiblemisfires.
4-3-20. Combination Initiation. If combination initiation is used, thefollowing procedures are to be used:
a. a non-electric initiation set is prepared taking into consideration thewalking time back to the firing point;
b. upon command of the authorized commander, both initiation sets areconnected to the ring main;
c. the firing party signals it's intention to fire as described previously;
d. the non-electric initiation set is fired; and
e. the firing party then walks back to the firing point and completes theelectric initiation procedure.
4-3-21. After Firing. Depending on the situation and if the demolition issuccessful, the following procedure shall be followed:
a. discontinuity is verified and the cable ends are shunted and grounded;
b. the designated person will ensure that the site is inspected to ensure alldemolition charges have fired;
c. once the all clear has been given, normally by voice, whistle or horn(one fifteen second blast) secondary tasks such as mining, boobytrapping can be completed; and
d. the effectiveness of the demolition and any other information arereported as required.
4-3-22. Misfires. If the tactical situation allows, the firing circuit and chargeswill be tested and inspected to find the fault, corrected and then initiated again.
a. In the event that the demolition fails, adhere to the specified waitingperiod for misfires as follows:
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(1) non-electric initiation or igniters electric. Minimum thirtyminutes;
(2) electric initiation. Ten minutes; and
(3) combination initiation. As for non-electric initiation, if the chargeis buried, follow the procedures in Chapter 7.
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ANNEX AINSTRUCTIONAL, TRAINING AND EXERCISE SAFETY DISTANCES
Ser Charge type Target Charge size Danger area radius (m)(Note 1)
Remarks
(a) (b) (c) (d) (e) (f)1 Electric detonators
and detonating cord In the open - 20 If detonating cord clips are used
the min safety distance - 100 m
2 Charges for battle inoculation and demonstrations
In the open As per local Range Standing Orders a. on stone free ground:charge x 40 m (min 100 m)b. on stony ground: charge x60 m (min 100 m)
3 Charges for battle inoculation on stone free ground
In the open a.Troops static-max 10 kg
b. Troops mobile - max 0.5 kg
0-0.5 kg 300.5-1 kg 601-2 kg 702-3 kg 803-4 kg 90
4-5 kg 1005-10 kg 120
a. If detonating cord clips usedthe min safety dist - 100 m
b. Charges are not to be covered
4 As for serial 3 but on stony ground
In the open As for serial 3 0-0.5 kg 60 0.5-1 kg 80 1-2 kg 90 2-3 kg 100 3-4 kg 120 4-5 kg 140 5-10 kg180
If detonating cord clips used min safety dist- 100 m
5 Cutting a. Timber b. Concrete c. Metal (girders, guns and vehicles)
Limited by local Range Standing Orders
a. 300 b. 500 c. 1000
6 Concussion Buildings and AFVs As for serial 5 1000
7 Cratering Roads, runways and railways
a. up to 2kg b. 2-30 kg c. over 30 kg
a. 100 b. 300 c. 500
Includes explosive aid to digging.
8 Buried Piers, abutments and retaining walls
As for serial 5 500
9 Borehole a. Timber b. Rock, masonary, concrete and brick
As for serial 5 a. 300 b. 500
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Ser Charge type Target Charge size Danger area radius (m)(Note 1)
beams and slabs, mass concrete walls and obstacles
As for serial 5 1000
11 Bangalore Torpedo (Commercially manufactured)
Wire Obstacles a. 1000 b. 200 c. 100
a. Perpendicular (right angles) to torpedo axis b. Standing in line with axis c. Lying in line with axis
12 Shaped Charges Concrete, steel or armour plate
a. Conical (1) Charge Demolition, 15 lbs, M2A4 (6.8 kg HE)(2) Charge Demolition, 40 lbs, M3A1(18.1 kg HE) (3) DREScavator, (10 kg HE)
b. Linear (1) Charge Demoliton, No. 14,11 lbs, MK 1 (5 kg HE) (2) Charge Demolition, 10 kg, TrigranC24 DREStructor
a. (1) 400
(2) 500
(3) 500
b. (1) 300
(2) 400
Includes mines used for expedient charges.
Distances in column (e) are for shaped charges fired vertically. When fired in another plane, the danger area in line with the molten slug shall be 1000 m.
13 Underwater Distances are similar to distances for charges on land.
Charges shall not be detonated until divers or swimmers have left the water.
14 Improvised charges Improvised charge safety distances are governed by the most hazardous construction material used in the charge or the target. If either the charge or target contain the following materials the associated safety distance will be used: a. Wood, Plastic or Glass - 300 m b. Concrete - 500 m c. Steel - 1000 m
NOTES 1. These danger areas shall be observed in peacetime when adequate cover is not provided.2. This figure includes all charge types described in this publication.
Fig 4A-1 Instructional, training and exercise safety distances
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ANNEX BOPERATIONAL SAFETY DISTANCES
WARNING: OPERATIONAL DEMOLITIONS USE ONLY (DO NOT EXTRAPOLATE)Injury from Blast (Notes 1, 3 and 4) Damage to Property (Notes 1, 3 and 4)
Ser Weight of explosive (kg)
Distance at which personnel are safe, provided they have adequate protection (ie, inside a trench or AFV) from fragments and debris (m)
Distance up to which person- nel suffer a- cute aural dis- comfort and possibly some ear damage (m)
Distance up to which there is a likelihood of ear injury and possibility of more serious injury (m)
Distance up to which personnel may sustain serious but probably not fatal injury and there is danger of fatalities by blast pressure or by sudden displace- ment (m)
Average dis- tance up to which minor house damage occurs (m)
Average dis- tance up to which houses are rendered uninhabitable. Extensive repairs are necessary (m)
Average dis- tance up to which houses are badly da- maged and require de- molition (m)
Average distance up to which 50% of glass is broken (Note 2) (m)
Injury from Blast (Notes 1, 3 and 4) Damage to Property (Notes 1, 3 and 4)
Ser Weight of explosive (kg)
Distance at which personnel are safe, provided they have adequate protection (ie, inside a trench or AFV) from fragments and debris (m)
Distance up to which person- nel suffer a- cute aural dis- comfort and possibly some ear damage (m)
Distance up to which there is a likelihood of ear injury and possibility of more serious injury (m)
Distance up to which personnel may sustain serious but probably not fatal injury and there is danger of fatalities by blast pressure or by sudden displace- ment (m)
Average dis- tance up to which minor house damage occurs (m)
Average dis- tance up to which houses are rendered uninhabitable. Extensive repairs are necessary (m)
Average dis- tance up to which houses are badly da- maged and require de- molition (m)
Average distance up to which 50% of glass is broken (Note 2) (m)
25 5,000 190 110 60 50 105 200 350 860 Notes: 1. Distances have been rounded off to the next highest 5 metres.
2. 10% of glass is broken at twice these distances, and usual limit of glass breakage is three times these distances.3. These distances are for blast effect only. Protection must be sought from flying debris.4. Figures are for Service Plastic Explosives.
Fig 4B-1 Operational safety distances
WARNING: OPERATIONAL DEMOLITIONS USE ONLY (DO NOT EXTRAPOLATE)
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CHAPTER 5TYPICAL DEMOLITION TASKS
SECTION 1GENERAL
OBJECTIVE
5-1-1. The tactical aim of a demolition task must be clearly understoodbecause it influences the technical methods employed to destroy the target. Forevery task, there is a minimum amount of damage or destruction necessary toachieve the aim, and it will be done efficiently using the available time, manpowerand resources. To exceed the damage necessary for the objective is a waste ofeffort and resources.
OBSTACLE
5-1-2. Particular attention shall always be given to restricting any repair of theobstacle. This can be done by laying mines, booby-traps, or crating theapproaches to the target. The following sections describe methods of causingeffective damage to some of the more important types of demolition targets. Itshall also be remembered that some targets can be more effectively and easilydestroyed by non-explosive methods.
GAP SIZE
5-1-3. The obstacle gap created will normally exceed the maximum spancapability of enemy assault bridging. This is taken as a minimum of 40 m. Thegap size or denial effectiveness can be increased by the use of mines, booby traps,fencing and debris.
CONSTRUCTION
5-1-4. Demolitions can also be used on several construction applications ifheavy equipment is not available, including:
a. excavating for field fortifications and antitank ditches;
b. land clearing of trees, stumps and boulders;
c. obstacle clearance; and
d. clearance of ice and log jams.
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5-1-5. B-GL-320-009/FP-001 discusses the use of explosives for excavatingfield fortifications including land clearing, cratering, ditching and ice demolitions
ROCK BLASTING
5-1-6. Rock blasting is the start of the rock production cycle in quarryoperations. Military explosives are not normally used for this task. There is awide range of commercial explosives suitable for quarry blasting, differing inproperties for various situations. Therefore loading and firing techniques used inquarry blasting are quite different than the more common demolition tasks.Specific details concerning the use of explosives in quarry blasting are covered inB-GL-320-012/FP-004.
5-1-7. The nature of the rock blasting operation involves the drilling ofboreholes in large rock formations that are beyond the capacity of present militaryequipment, and specialized drilling patterns. The details of these and otheraspects of rock blasting are beyond the scope of this manual. However, a basicfamiliarization and understanding of terminology used in quarry blasting isbeneficial. The engineer executing any small rock blasting task must observe theresults and be prepared to modify patterns, explosive quantities and methods toachieve the best results.
5-1-8. Terminology. The following terms relating to quarrying are used inthis section:
a. burden - the distance measured from the explosive to the face;
b. collar - the open end of the drill hole;
c. cut - the opening holes of an excavation designed to provide "relief" forlater holes to break toward;
d. cut-off - a failure caused by ground movement cutting-off a column ofexplosives or detonating cord before it can fire, caused by improper useof delay devices;
e. face - the rock surface to be excavated;
f. grade - the floor of the quarry;
g. load factor - the quantity of explosive used per cubic metre of materialexcavated. Sometimes called a powder factor;
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h. muck pile - the broken rock from a blast; and
j. toe - the bottom of the quarry face.
5-1-9. Principles of rock excavation. The aim of rock excavation is toachieve the desired breakage with a minimum of drilling and explosive. Toachieve this aim the following points must be considered:
a. the tendency of the rock to break away when explosives are fired("relieving" the holes);
b. the borehole blast design and sequence of firing;
c. the loading of the explosives into the holes; and
d. the geological factors such as the strength of the rock.
5-1-10. Relief. If a single hole was drilled deep into a large rock surface andexploded, one could expect to produce some radial cracks and perhaps somebreakage at the entrance of the hole, because the rock has no room for movement.If the hole is drilled near the open face, and exploded the rock is relieved into theface. This is the basic principle of quarrying, "to shoot to a relief face".
5-1-11. The first step in quarrying is to provide the relief face. If the facealready exists naturally, much effort can be saved. If a natural face cannot befound, a cut must be made to produce the face. This cut is made by drilling a gridof boreholes with a spacing approximately equal to the depth of the boreholes.After firing, the loose rock is removed and if necessary further holes are fired untila face of sufficient height is developed.
5-1-12. Having established a face, quarrying can begin by drilling and firinglines of boreholes at the face. These boreholes generally give the best resultswhen drilled vertically from the top, but horizontal boreholes may be used.B-GL-320-012/FP-004 illustrates blast patterns.
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SECTION 2ROAD SYSTEMS (LESS BRIDGES)
SITES FOR ATTACK
5-2-1. The extent to which roads can be destroyed will vary from a simplecrater obstacle to a route denial belt which blocks in depth all routes within it.Apart from bridge demolitions, the technical problem is simple.
5-2-2. The site chosen shall be one which cannot be easily by-passed andwhere there is difficulty in deploying repair equipment. Ripping only breaks upthe road pavement whereas explosives are used to attack the subgrade and ifpossible, the drainage system. Flooding will hinder repairs and cause prolongedmaintenance troubles. Suitable sites for attack are:
a. Bridges Approaches. Where the stream or gap is too small to providea sufficient obstacle in itself, the approaches shall be destroyed as well.
b. Culverts. Charges laid in culverts shall be well tamped if they are todestroy the road as well. They are seldom worth using as singleobstacles. However, if the aim is to block the drainage system, thedestruction of a culvert is a quick way of achieving it.
c. Fords. Effective obstacles can be created at fords, and causeways overmarshy ground by cratering, flooding and mining.
d. Escarpments or steep hill sides. The charge should be designed toblow outwards as well as upwards. It is better to blow away the road,rather than to bring down the hill-side on top of it, as this may permitthe use of the road after clearance of the debris.
e. Embankments. Embankments are often difficult to by-pass if blocked,particularly in marshy areas.
f. Cuttings. In deep cuttings with steep sides, blowing in the sides of thecutting may create a more effective obstacle. Craters within cuttingsare ineffective because the debris would fall back into the obstacle.
g. Woods. Obstacles shall be created in wooded areas at points where theundergrowth or the trees are so dense that to construct a detour requiresconsiderable effort.
h. Road junctions and level crossings. An excellent means of blockingtwo routes in one demolition.
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j. Towns and villages. These sometimes afford good obstacle sites, buteven if all sides streets are blocked as well as the main thoroughfare, abypass route can quickly be made by demolishing a few buildings, andthere is always ample local material to fill in craters.
k. Road Tunnels. Road tunnels provide a choke point on a road and aretherefore good demolition targets. The best points of attack are placeswhere it passes through loose or shifting ground.
5-2-3. The main consideration with a large route denial operation is to keepplanning simple. It is important to ensure that all axial roads are damaged to thesame degree to prevent bypass. The general method of attack may vary with thenature of the road. In some cases, denial can be quick and more effective bysimply blowing a single bridge or a short length of road in a good defile, insteadof destroying many miles of road surface itself.
ROUTE DENIAL OBSTACLES
5-2-4. The emplacing of route denial obstacles involves the progressiveexecution of explosive or non-explosive obstacles along one or more routes infront of an opposing force. Generally used during defensive operations as part ofa major obstacle belt, route denial obstacles can also be employed during the delayor covering force battle and withdrawal operations. Use of scatterable mines,preplanned artillery fire plans and prepared obstacles can effectively enhanceroute denial obstacles if coordinated early in the operational planning process. Inorder for route denial obstacles to be effective, they must be executed quickly andefficiently using well trained troop, section and sub-section drills.
5-2-5. There are two methods of emplacing route denial obstacles. The morecommonly known Rapid Route Denial (RRD) method and the newer SystematicRoute Denial (SRD) method. An understanding of the concepts and theemployment of standard drills of each method is critical in the choice of whichmethod is to be used. What is also appropriate in making the choice, particularlyto the engineer troop commander on the ground, is an understanding of allavailable techniques to emplace the obstacle, their advantages and disadvantages,limitations and circumstances which favour their use. It is the officer's functionbased on his tasking and detailed reconnaissance, to select the best method suitedfor a particular situation.
RAPID ROUTE DENIAL
5-2-6. Rapid route denial was developed to optimize the rapid development ofa major obstacle belt of perhaps twelve or more multi-crater sites. The method
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works well only when all sites are preliminary demolitions. The method uses anassembly line technique with concurrent activity from the various parties involved- recce party, chamber party, charging and ring main party, and firing and miningparties. This method is impractical for small operations since there is generallynot enough time to bring the "assembly line" up to speed. There are severaladvantages and disadvantages to the rapid route denial method.
a. Advantages.
(1) the first crater obstacle is created much quicker than by any othermethod;
(2) none of the prepared sites require protection by demolition guardsor firing parties;
(3) time lost due to travel between the site and safe area for each stepof the procedure is significantly reduced; and
(4) all parties can prepare for their specific sub-task at each site ratherthan each field section preparing for all sub-tasks at one site.
b. Disadvantages.
(1) field troops must reorganize into the required parties and sectionstores and equipment redistributed, thus disrupting the establishedchain of command and section integrity;
(2) the method is more vulnerable to enemy action or vehiclebreakdown. Work will not continue until a new party isconstituted, tasks are reallocated or transport redistributed;
(3) the method is overly dependent on the single troop ammunitionvehicle. Conflicting requirements for the ammunition vehicle tobe moving rearward to be resupplied at the same time of a routedenial operation can cause timing problems. The charging andmining parties will require dedicated vehicle support (probably theammunition vehicle) to transport the large quantities of explosivesand mines necessary to complete all of the target sites;
(4) site control and continuity will be difficult as no singlecommander will oversee the preparation of the target from start tofinish. This may result in confusion and will cause lost time aseach party becomes familiar with each new location.
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5-2-7. As can be seen by the list of advantages and disadvantages, carefulmission analysis and a thorough knowledge of both tactical and technicalsituations are required. It is reiterated that this method was originally, and still is,intended or suited to a crater obstacle route denial task. Employment of thismethod for abatis, wire obstacle, booby trapping or other improvised non-explosive obstacles is not recommended.
SYSTEMATIC ROUTE DENIAL
5-2-8. Systematic route denial is a system of leap-frogging engineer sectionsfrom target to target along the route to be denied. It has been considered to be aless sophisticated system, which is easily understood and implemented. It isfurther argued that it is a very quick and flexible system that requires littlereorganization, easily initiated and operationally effective during times of radiosilence.
5-2-9. During the systematic route denial method, field sections are givenorders to execute one or more complete obstacles rather than to perform a specificsub-task. The method involves leap-frogging, rearward, the lead section (sectionclosest to the enemy) through other field sections that are preparing subsequentobstacles along the route. Once the lead section has cleared the other workingsections, they can be resupplied or reconstituted to start working on the nextobstacle in the chain of tasks or ordered to some other task. This method isparticularly useful for small operations where there are insufficient numbers ofobstacles to bring the rapid route denial assembly line up to speed or not all theobstacles are of the same type. Advantages and disadvantages to the systematicroute denial method are as follows:
a. Advantages:
(1) a single field section commander is responsible for the obstacletask from start to finish minimizing confusion of orders;
(2) command and control is maintained at all times even underconditions of radio silence. If the particular situation calls for it,the field troop commander is on site for the authorization toexecute the firing of any explosive charges in the event that thetactical situation changes and a difficult judgement call needs tobe made in the event of pending failure, capture or enemy action;
(3) preparation or reorganization time for the field sections is minimaldue to the organization of section basic loads;
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(4) the system is flexible in that any number of field sections can beattached or detached from the troop with no change in commandand control procedures. Any number of targets can be attackedwithout complicating the troop resupply system;
(5) administrative control can still be maintained even if the troop issplit on two routes;
(6) the success of the total operation does not depend as heavily oneach party doing its assigned sub-task; and
(7) the troop ammunition vehicle is free to move back to the echelonfor replenishment as each section carries a basic load, orindividual basic loads can be adjusted to suit particular obstacletasks.
b. Disadvantages:
(1) the systematic route denial method can be inefficient in time andresources. The employment of a complete field section on a"simple" obstacle such as a wire fence obstacle, or small booby-trap obstacle that may require a half-section working party thatcould have been dropped-off then picked-up after completion, hasutilized the truck/APC resource, the auger, the explosives andmines carrying capability or even the dozer capability;
(2) the concept of leap-frogging of sections through each other, on theground, actually translates to delicate vehicle manoeuvringthrough, over or around the different obstacle sites being preparedwhich must be correctly coordinated and timed.
5-2-10. Regardless of these comparisons between the two methods, theprinciple point is that no single drill, technique or method can be applied in everysituation. Knowing all the aspects of the engineer operation to be completed willenable the engineer commander to select the proper method to conduct routedenial tasks as the situation dictates. With properly trained field sections, goodleadership and sufficient resources, either method can be used as is or modified asapplicable.
METHODS OF ATTACK
5-2-11. Cratering Charges. Roads are best destroyed by cratering at pointswhere the building density or terrain features preclude direct bypassing of the
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obstacle. Preparation of road craters at turns in the road increases theireffectiveness since this will make armoured vehicle launched bridging moredifficult. Charges may be buried in the subgrade by one of the methods describedin Chapter 6. In cases where the ground water table is high, placing buriedcharges will be difficult. A deep crater filled with water creates a more effectiveobstacle.
5-2-12. Manholes, sewers, and culverts may provide readily usable chargechambers for craters. Normal rules for spacing of these buried charges shall beobserved. If more than one charge is used, no stemming is required betweencharges, but stemming must be placed from the outside charges to the outerextremities of the demolition as shown in Fig 6-6-2.
5-2-13. Culverts are blocked to cause flooding. A cutting charge proppedagainst the underside of the arch over a length of three metres should ensuresufficient collapse to block it.
RIPPING
5-2-14. Rippers on dozers and scarifiers on graders can penetrate hard ground,rock or road pavement material and break it up to enable further obstacleenhancement. Large sections of concrete surfaces are simply broken up oroverturned to expose the subgrade. Ripping or scarifying shall be supplementedby antitank mines or by a crater every 50 m to deny the road.
TUNNELS
5-2-15. The best point to attack atunnel is where it passes throughunstable ground. The brick or masonrylining shall be destroyed along 15 to 25m by a series of small charges placed inor behind the lining by the boreholemethod at a height of about 1 m. If theborehole method is impracticable, acutting charge should be used. It isoften sufficient to destroy one side ofthe arch ring in this manner. Theweight of the over- burden will bringdown the roof and fill the section oftunnel. In solid rock, the destruction ofthe lining, if any, will often have littleeffect, and large breaching charges
Fig 5-2-1 Demolition of tunnelin hard ground orrock
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must be used. A very effective obstacle can be created by laying three charges (atright), however a great deal of work is required to place the charges. The use of aventilating shaft as the chamber for the charge, will often save time and effort.
ABATIS
5-2-16. Trees felled can be used to block a road or defile. To stop trackedvehicles the trees should be at least 0.6 m in diameter and 6 m tall. Trees selectedcan be felled by explosives, chainsaw, or hand-axe and saw, but are felled so thatthe trunk remains attached to the stump. To stop wheeled vehicles the diameter ofthe trees may be smaller, although the remaining characteristics remain the same.Barbed wire, antitank mines, or booby-traps greatly increase the effectiveness.Abatis can be light or heavy:
a. Light abatis. This is 20 to 50 m deep. If constructed with explosives,1 to 1.5 hours work by a section is required.
b. Heavy abatis. This is 50 to 100 m deep. If constructed withexplosives, 2 to 3 hours work by a section is required.
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SECTION 3BRIDGES
GENERAL
5-3-1. The aim of bridge demolition is to create a gap large enough to makebreaching, bypassing or repairs impracticable, and to force the enemy to re-bridgeon a less favourable site.
5-3-2. Size of Gap. The gap required normally exceeds the maximum spancapability of assault bridging equipment of the opposing force. This is taken as aminimum of 40 m. If the total gap spanned by a bridge is too small to restrict theuse of assault bridging, the gap may be increased by destroying the abutments andcratering the immediate approaches. In this case, all adjacent sites suitable forbridging are also to be destroyed.
5-3-3. Degree of Destruction. The complete demolition of a bridge usuallyinvolves the destruction of all the components such as the spans, piers (if any),and the abutments. Complete demolition may be justified in cases where theterrain forces the enemy to reconstruct on the same site, but this is normally notrequired to meet the tactical objective. The method of attack is always selected toachieve the tactical objective with the minimum expenditure of resources.
5-3-4. Debris. Debris may causeserious construction delays if it isobstructing the gap. It also providesexcellent cover for antitank mines andbooby-traps. Whenever possible,bridges shall be demolished in such away that the resulting debris imposesthe maximum hindrance to recon-struction. For example, it could be awaste of resources to completelydestroy the spans, piers and abutmentsof a bridge if the rubble from theabutments could readily be improvedby dozing to provide ramps for aabutments could readily be improvedby dozing to provide ramps for a
Fig 5-3-1 Use of debris to delayrebridging.
floating bridge. Leaving a "saw-tooth" pattern of debris (Fig 5-3-1) above thewater level poses a difficult problem to overcome.
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5-3-5. Stages of Preparation. When planning a bridge demolition operation,it is essential that the first priority be the creation of a gap. This may require a onestage or a two stage attack. Further tasks to improve the obstacle can follow if thesituation permits, including:
a. cratering and mining abutments;
b. destruction of piers; and
c. cratering and mining approaches and alternate crossing sites.
PRINCIPLES OF BRIDGE DEMOLITION
5-3-6. If the engineer officer or NCO fails to recognize the characteristics ofthe target, the results of a demolition may be quite different from those expected.To overcome this, two concepts are used: collapse mechanism, and bridgecategorization.
COLLAPSE MECHANISM
5-3-7. General. There are two minimum conditions for a successful bridgedemolition:
a. a collapse mechanism mustbe formed; and
b. once formed, the collapsemechanism must be free tomove far enough to createthe desired obstacle.
Fig 5-3-2 No collapse mechanism
5-3-8. Condition 1 - A collapse mechanism. Under normal conditions abridge is a stable structure. In bridge demolitions the aim is to destroy certainparts of the bridge, causing the bridge to become unstable and to collapse under itsown weight. That is, a hinge mechanism must be formed. This may involve theformation of hinges on various parts of the bridge. Fig 5-3-2 shows the lack of acollapse mechanism.
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5-3-9. Condition 2 – Free-dom of Movement. Onceformed, the collapse mechanismmust be free to move far enoughunder its own weight to createthe desired obstacle otherwise itwill jam and will not create thedesired result (Fig 5-3-3). Thismay require cropping of thebridge, abutment, or pier. Fig 5-3-3 Jammed collapse mechanism
5-3-10. Types of CollapseMechanism. There are threetypes of collapse mechanism(Fig 5-3-4) that may be formedby demolition.
a. the see-saw;
b. the beam; and
c. the member withoutsupport.
Fig 5-3-4 Types of collapse mechanismBRIDGE CATEGORIZATION
5-3-11. General. The first step necessary to achieve an efficient bridgedemolition is to categorize a bridge correctly. The term "categorization" has beenadopted to avoid confusion with the term "classification" which is concerned withthe load carrying capacity of bridges. The correct categorization of bridgescoupled with an elementary knowledge of bridge design allows a suitable methodof attack to be selected.
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5-3-12. Categories. All bridges can be placed into one of three categories:
Fig 5-3-5 Simply supported bridge spans
a. Simply Supported. A bridge is simply supported when an individualspan is supported at each end without rotational restraint and with atleast one end free to move horizontally. The theoretically ideal simplysupported bridge is shown in Fig 5-3-5. The free bearing representsanybearing which allows some horizontal movement (for expansion andcontraction due to temperature), e.g. roller bearings, sliding bearings,rubber bearing pads, etc. Multi-span bridges may consist of severalsimply supported spans.
b. Continuous. "Continuous" has a wider meaning than that of a multi-span continuous beam bridge, as would normally be implied. Fordemolition purposes, cantilever, portal and arch bridges are consideredas continuous for the determination of the method of attack. If a bridgedoes not belong to the miscellaneous category and is not simplysupported, the rule of thumb is to categorize it as "continuous".
c. Miscellaneous. This category forms a small proportion of bridgestructures. The method of attack for this category must be worked outfrom first principles. Examples of this category are suspension bridges,swing or lift bridges, and cable stayed bridges.
5-3-13. Differentiation Between Categories. There are a number ofguidelines which are used to differentiate between simply supported andcontinuous bridges. These are described be-low and shown here.
a. Continuity. Multi-span simply supported bridges usually have distinctbreaks over the piers. In Fig 5-3-6, two simply supported spans areindicated because of the discontinuity of the bridge at the pier. Incomparison, the main structural members of a continuous bridge arecontinuous over intermediate piers.
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Fig 5-3-6 Identification of simply supported and continuous spans
b. Construction depth. In multi-span simply supported bridges theconstruction depth of the span may decrease at the piers as in Fig 5-3-6,whereas in continuous bridges it frequently increases at the piers.
c. Flange thickness. This guideline applies only to steel plate girderbridges. In simply supported bridges the thickness flange platefrequently increases at mid-span, whereas in continuous bridges itfrequently increases over the piers.
d. Bearings. Multi-span simply supported bridges require two lines ofbearings at the piers; continuous bridges only one.
e. Guiding Rule. The external appearance of a bridge can sometimes bedeceptive. Whenever possible, construction drawings should beconsulted to ascertain the correct category. However, if this is notpossible and if there is any uncertainty about the support condition of abridge span, the guiding rule is to always assume CONTINUOUS. Theuse of this rule always results in the selection of an adequate method ofattack.
However, failure to recognize the simply supported condition will invariablyresult in unnecessary demolition effort.
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CATEGORIZATION OF SIMPLY SUPPORTED BRIDGES
5-3-14. The categorization chart for simply supported bridges (Fig 5-3-7), isentered from the left, and lines and arrows are followed across to the right. Theroute selected includes all categorization terms applicable to a particular bridge.
5-3-15. Sub-Categories.There are four main sub-categories: steel beam, steeltruss, concrete beam/slab, andbowstring. The first three can besub-divided further into deckbridges, where the load is carriedon top of the main structuralmembers, or through bridgeswhere the load is carriedbetween the main structuralmembers. For deck bridges it isnecessary to determine thelocation of bearings
Fig 5-3-7 Simply supportedcategorization chart
(i.e. supporting the top chord/flange or the bottom chord/flange), as this has aninfluence on the possibility of jamming during demolition.
5-3-16. Definitions. The terms usedin the simply supported categorizationchart are explained below.
a. Steel beam bridge. Thissub-category includes normalsteel beams, plate girders,and box girder spans.Typical cross sections areshown at the right.
Fig 5-3-8 Steel beam bridgetypical cross-sections
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b. Steel truss bridge.There are manyvarieties of trussesused in bridgedesign, however alltruss bridges containdiagonal members.Side elevations forthe three normalconfigurations areshown here.
Fig 5-3-9 Steel truss bridges
c. Concrete beam/slab bridge. For categorization purposes there is noneed to distinguish between reinforced and pre-stressed concretebridges, as methods of attack are the same. Fig 5-3-10 shows mid-spancross-sections of types of concrete bridges most likely to beencountered. At the mid-span, the majority of steel reinforcing rods ortendons are located in the bottom section of the bridge, which is themost difficult part to attack with the current range of explosives. Thisfact has been considered in recommending the methods of attack forconcrete bridges.
d. Bowstring bridge. The normal bowstring has the form shown above.The bow may be a steel beam, box girder, concrete beam, or steel truss,and is mainly in compression. The deck acts as a tie and resists theoutward force applied by the bow. The deck is designed as a weakbeam spanning between hangers with no diagonal bracing between thehangers.
Fig 5-3-12 Simply supported, bowstring,reinforced
e. Reinforced bowstring bridge. Occasionally a bowstring is used toreinforce a large steel beam/truss bridge. This type of bridge iscategorized as a simply supported bowstring, reinforced (Fig 5-3-12).The existence of a steel beam or steel truss extending the full length ofthe entire span indicates that a bowstring bridge shall be regarded as"reinforced".
f. Arch bridge. A bridge of theform shown in Fig 5-3-13 isnot a bowstring. It is an arch;the outward forces of the archare restrained primarily by theabutments and not by the deck.The categorization of this typeof bridge is explained in thesection on continuous bridges.
Fig 5-3-13 Type of archbridge
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DEMOLITION OF SIMPLY SUPPORTED BRIDGE
5-3-17. Reconnaissance. The reconnaissance procedure for simplysupported bridges is:
a. categorize the bridgeas directed in theprecedingparagraphs;
b. take the followingmeasurements(Fig 5-3-14);
Fig 5-3-14 Measurements of simplysupported spans
(1) length of bridge L in metres. (Note that this is not the width of thegap itself, but the actual length of the longitudinal members whichsupport the deck); do this for each span,
(2) beam/truss/bow depth H in metres. This dimension includes thedeck,
(3) total end clearance E in metres. This is the sum of the endclearances at both ends of the span, and
(4) the mean of the bearing support lengths Ls in metres at each end ofthe span. This is the average of the lengths from the end of thespan to the face of the abutment or pier;
c. determine the method of attack; and
d. take detailed measurements required for charge calculations at thepoints of attack.
5-3-18. Point of attack. The point of attack will be at, or near mid-spanbecause bending moments due to the bridge span's weight are at a maximum atmid-span, and the likelihood of jamming during collapse is reduced.
5-3-19. Line of attack. The line of attack will be parallel to the lines of theabutments as shown in Fig 5-3-15. This reduces the risk of restraining momentsforming about opposite corners of the bridge, which could prevent collapse underit's own weight. Bridges shall therefore be demolished without twisting. If therecommended line of attack involves
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cutting across transverse beams, the line shall be repositioned to cut betweenadjacent trans-verse beams.
5-3-20. Methods of attack.The methods of attack are shownin Annex A to this Chapter. Themethod likely to produce the mosteconomical solution is describedfirst. Within each category thereare variations in detailedconstruction, span, loading (e.g.road, rail, or both), gap and Fig 5-3-15 Lines of attack
abutment conditions which influence the selection of the most suitable method.Thus, the method of attack first recommended in Annex A may not always be themost suitable. The selection of the best method of attack rests with the officer orNCO who carries out the reconnaissance. The three recommended methods ofattacking a simply supported bridge span are a bottom attack, a top attack, or anangled attack. In all cases, it is necessary to ensure that jamming does not occurduring collapses.
5-3-21. Bottom attack. For a bottom attack, it is necessary to have sufficientend clearance. The required end clearance (ER) to prevent jamming can bedetermined from Fig 5-3-16. If the total end clearance (E), is greater than therequired clearance (ER), jamming will not occur and a bottom attack can be used.If E is less then ER then a top or angled attack is required, or the required endclearance must be created by:
a. cropping the bottom corners of the bridge at one abutment; or
b. destroying one abutment at the places where jamming would occur.
Ser H/L ER/L Ser H/L ER/L(a) (b) (c) (a) (b) (c)10 0.10 0.020 20 0.20 0.077
Based on ER/L = [ 4x(H/L)2 + 1 ]1/2 - 1Fig 5-3-16 Required end clearance (ER) at supports for mid-span bottom
attack
5-3-22. Top attack. For a top attack, if it is necessary to remove a section atmid-span from the top of the bridge, the length of cut (Lc) to be removed iscalculated using the table at Fig 5-3-17. The correct (Lc) will ensure the removalof the V-shaped cross section from the span required to prevent jamming. Thedepth of the V-shaped section is the full depth of the target.
5-3-23. Angled attack. For angled attacks, all members including handrailsand service pipes must be cut. The angle of attack shall be about 70o to thehorizontal to prevent jamming. The location of the attack shall be between themid-span point and a point one-third (1/3) from one end. Some latitude inselecting the point of attack is allowed to reduce the need for changes to methodsof attack. Figures showing methods of attack are provided at Annex A to thischapter.
5-3-24. Concrete bridges. For concrete bridges other than reinforced orprestressed concrete slab bridges, no bottom attack method has been included inAnnex A. A bottom attack will be preferred once explosive charges capable ofsevering steel and concrete to depths greater than 0.15 m are introduced intoservice. In a top attack, all concrete within the indicated V-shaped section (Lc)must be removed to cut the span. A concrete stripping charge must be applied toachieve this. There is no requirement to cut steel reinforcing rods.
5-3-25. The table at Fig 5-3-17 is based on this formula :
Fig 5-3-17 Minimum length of section to be removed (LC) for a mid span attack
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5-3-26. Example Bottom Attack.
a. Category. Simply Supported, Steel Beam, Deck Bridge, BottomSupport.
b. Reconnaissance Measurements. L = 25 m, H = 2.25 m, E = 0.45 m.
c. Method of Attack. The method of attack recommended in Annex A isBottom Attack, provided that E is greater than ER. To determine this,the following calculations are required:
(1) H/L = 2.25/25 = 0.09;
(2) From Figure 5-3-16, using H/L =0.09, determine the end clearancerequired which is 0.016;
(3) ER = 0.016 x L = 0.016 x 25 = 0.4 m; and
(4) Since 0.45 m is greater than 0.4 m, a bottom attack can be usedwithout any likelihood of jamming during collapse.
5-3-27. Example Top Attack.
a. Category. Simply supported, bowstring, normal.
b. Reconnaissance measurements. L = 62 m, H = 8.5 m, LS = 1.15 m.
c. Method of Attack. The method of attack recommended in Annex A istop attack. It is necessary to ensure that the length of top attack isadequate. To determine this, the following calculations are required:
(1) H/L = 8.5m/62m = 0.137;
(2) Ls/L = 1.15m/62m = 0.0186;
(3) From Fig 5-3-17, the calculated values for H/L and LS/L arerounded up to the nearest value listed on the table. In this caseH/L becomes 0.019 and LS/L becomes 0.019. If either or both ofthe H/L or LS/L values exceed those listed on the table, the LCLvalue may be calculated using the equation at para 5-3-25. Thisequation may also be used to give a more precise LCL value forany H/L or V values.
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(4) LcL= 0.079 therefore LC = 0.079 x L = 0.079 x 62 m = 4.898 m(rounded to 4.9 m); and
(5) From the value at (4), cuts will be required 2.45 m on either sideof midspan.
CATEGORIZATION OF CONTINUOUS BRIDGES
Fig 5-3-18 Continuous bridge categorization chart
5-3-28. Categories. The categorization chart for continuous bridges is in Fig5-3-18. The chart is used in the same manner as the chart for simply supportedbridges. There are six main sub-categories: Cantilever, Cantilever andSuspended Span, Beam/Truss, Portal, Arch, and Masonry Arch. It is necessary todifferentiate between steel and concrete construction for the first five sub-categories as different methods of attack exist for each. If a continuous bridge isof steel and concrete construction (e.g. steel beams supporting a reinforcedconcrete deck), the decision whether the bridge is continuous steel, or continuousconcrete will be dependent on the material of construction of the mainlongitudinal load bearing members.
5-3-29. Cantilever bridge.This category of bridge is shown atFig 5-3-19 and is identified by themid-span shear joint. The fulllengths of the anchor spans may onrare occasions, be built intoabutments, making identificationof the cantilever principle difficult.Review construction Fig 5-3-19 Cantilever bridge
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drawings whenever these drawings exist, so that details hidden from view can beconsidered during categorization.
5-3-30. Cantilever and suspended span bridge. This category of bridge isillustrated in Fig 5-3-20. If the length of suspended span creates a40 m gap, then it shall beattacked as the work involvedin preparation is less. In such acase, use the simply supportedcate-gorization chart.
5-3-31. Beam/truss bridge.It is necessary to differentiatebetween a beam/truss bridgewith all spans of similar lengthand one with a short side span.The short side span is
Fig 5-3-20 Cantilever and suspended spanbridges
defined as being less than three-quarters of the length of the next span. Examplesof the beam/truss bridge are in Figs 5-3-21, 5-3-22 and 5-3-23.
Fig 5-3-21 Continuous, steel beam, without short side span
Fig 5-3-22 Continuous, steel beam, with short side span
Fig 5-3-23 Continuous, steel truss
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5-3-32. Portal bridge.Typical portal bridges areshown in Fig 5-3-24. It isnecessary to differentiatebetween portals with fixed orpinned footings as thisaffects the method of attack.Where doubt exists, a fixedfooting is assumed. Theportal bridge can bedifferentiated from the arch
Fig 5-3-24 Typical portal bridge
bridge by the fact that in all portal bridges, there is not a smooth curvebetween the leg of the span and the span itself.
5-3-33. Arch bridge. It isnecessary to specify whether ornot an arch bridge has an open orsolid spandrel, and fixed orpinned footings. Again, wheredoubt exists, a fixed footing isassumed. Fig 5-3-25 illustratestypical arch bridge shapes. Fig5-3-26 shows an solid spandrelarch and Fig 5-3-27 shows aopen spandrel arch.
5-3-34. Masonry arch bridge.This category is identified by thesegmental arch ring (Fig 5-3-28).Many reinforced concrete bridgesare faced with masonry and thiscould lead to incorrect categori-zation. Therefore always look atthe underside of the arch which
Fig 5-3-28 Continuous masonry arch
is rarely faced unless the bridge is a true masonry arch.
DEMOLITION OF CONTINUOUS BRIDGES
5-3-35. Reconnaissance. The reconnaissance procedure for continuous bridgesis:
a. categorize the bridge as directed in the preceding paragraphs;
b. take the following measurements (Fig 5-3-29);
Fig 5-3-29 Measurements of continuous bridges(1) span L in metres, for all spans, measured between centrelines of
bearings, and
(2) for arch and portal bridges, the rise H from springing line orbottom of support leg to deck or top of arch, whichever is thegreater,
c. determine from Annex B to this chapter the method of attack; and
d. take the detailed measurements required for charge calculations.
5-3-36. Points of Attack. No common point of attack rule exists for allcategories of continuous bridges.
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5-3-37. Line of Attack. The line of attack rule used for simply supportedbridges also applies to continuous bridges. The line of attack will be parallel tothe lines of the abutments. Bridges shall be demolished without twisting. If therecommended line of attack involves cutting across transverse beams, the lineshall be repositioned to cut between adjacent transverse beams.
5-3-38. Method of Attack. The method of attack for all continuous steelbridges demand complete cuts through the bridge span. Providing charges can beplaced where required, continuous bridges can be demolished using a single stageattack.
a. If concrete decks on steel beam bridges are particularly deep, thecharges designed to sever the deck may not sever all reinforcing steel.If a complete collapse does not result, a second stage attack must bemade. Consideration shall be given during reconnaissance to therequirement for a two stage attack for steel beam bridges with deepconcrete decks.
b. Continuous concrete bridges are the most difficult of all demolitiontargets, and shall not normally be reserved demolitions. Some sub-categories require complete severance of the span and thus a two stageattack, while for others, the removal of concrete (but not reinforcing) ina single stage attack will suffice. Some concrete arch bridges requirean additional attack at the springing line. Details are given in Annex B.
c. Where the removal of steel or concrete over a particular length of thespan is required, it is essential to ensure collapse results withoutjamming. The length of span to be removed can be calculated using theL and H values measured during reconnaissance and Fig 5-3-30.
d. Cuts in continuous bridges shall be angled at about 70o to the horizontalto prevent jamming during collapse. The angles shall allow freerotation if the seesaw collapse mechanism is intended, or anuninterrupted fall for the member without support.
e. For masonry arch bridges, no changes have been made to existingmethods of attack. For bridges which have been standing for a longperiod of time, attacking only the crown may not achieve collapse ofthe remainder of the bridge. Therefore when time permits, masonryarch bridges should be attacked at both haunches (side of arch betweenthe crown and the pier).
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f. With the exception of concrete arch bridges, only one method of attackis given in Annex B for each sub-category of continuous bridge. Forfixed footing concrete arch bridges, it is necessary to consider all spansseparately. If the span exceeds 40 m, removal of all concrete over themid-span section of length Lc will ensure collapse of the two resultingcantilevered arms. If the span is less than 40 m, removal of all concreteover the mid-span section of length Lc may not be sufficient to causecollapse. In this case, the springing will also be attacked or analternative method of attack, as described in Annex B, shall be used.
g. For continuous bridges where the recommended method of attackrequires the removal of concrete only, the concrete stripping chargemay be applied as for the simply supported bridges, and collapse willresult. For continuous bridges where the recommended method ofattack requires a complete cut through a span, the removal of concretewill achieve only the first stage of a two stage attack. It is notimpossible that the concrete stripping charge will achieve sufficientdamage to the steel reinforcement to cause collapse. However, inalmost all cases where a complete cut is recommended, the secondstage attack will be required, and it shall be planned for.
Fig 5-3-30 Minimum length of section to be removed for arch and pinnedfooting portal bridges
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5-3-39. Example of Calculation.
a. Category. Continuous, concrete, arch, open spandrel, pinned footing.
b. Reconnaissance measurements: L = 58 m, H = 7.5 m.
c. Length of section to be removed from span. The length of span alongwhich concrete shall be removed, Lc is calculated as follows:
(1) Calculated H/L = 7.5/58 = 0.129;
(2) From Figure 5-3-30. For each H/L value given, a value can beread which represents Lc/L. Interpolation may be used ifnecessary. For H/L = 0.129, Lc/L = 0.035; and
(3) Insert the measured value of L to find Lc.Lc = L x 0.035 = 58 m x .035 = 2.03 m.
d. Action. For Lc = 2.03 m, the thickness of bridge section should bemeasured 1.02 m to one side of the mid-span, and charge calculationsusing the concrete stripping charge formula should be completed.
DEMOLITION OF MISCELLANEOUS BRIDGES
5-3-40. General. Examples are suspension bridges, swing bridges, and liftbridges. These bridges are assessed and attacked using the following principles.
5-3-41. Suspension Bridges.
a. Large Bridges. For very large suspension bridges, the cables, towersand anchorages may prove too thick to be attacked effectively. In thiscase, the most economical method of attack is to cut an approach span,or to cut out a section of deck in the main span. This may be done bycutting the hangers from the main cables and by cutting the deck ateach end of the section to be removed.
b. Smaller Bridges. For smaller suspension bridges, the main steel cablesshall be cut. If the thickness of the steel is over 75 mm, linear shapedcharges shall be used. The cables may be attacked at the top of thesuspension towers, as they are easily cut at a point where they arefirmly supported. The top of the tower is likely to be destroyed as well.Another suitable method is to cut the suspension cables where theyemerge from their buried anchorages. According to the time available,cuts shall be made in the roadway, and the suspension towers and their
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footings shall be destroyed. The pier foundations and the buriedanchorages will probably be too massive to attack economically andtheir destruction shall not normally be attempted.
5-3-42. Swing Span Bridges. Basically, a swing span bridge is a continuousspan which can be rotated on its central pier. The arms of a swing span may ormay not be of equal length. If the arms are of unequal length, weights are addedto balance them. The weight of the bridge is carried on the central pier, usually onrollers which run on a circular track.However, in some designs theroller system is merely abalancing aid and the weightof the bridge is carried on acentral bearing. Fig 5-3-31illustrates a swing bridge. Inmost cases the swing span caneasily be recognized as a
Fig 5-3-31 Swing span truss bridge
continuous cantilever bridge and can be attacked accordingly. It may also bepossible and perhaps desirable to deny use of the bridge by rotating it to the openposition and then de- stroying the operating mechanism.
5-3-43. Lift Bridges. There are two types of lift bridges. The bascule bridgewith one or two leafs is illustrated in Figs 5-3-32 and 5-3-33. The vertical liftbridge is illustrated in Fig 5-3-34.
5-3-44. Bascule Bridge.
a. A critical examination of Figure 5-3-32 shows that this type of basculebridge can be categorized as a cantilever bridge. Note that there is ashear joint at mid-span and in this case, instead of an anchor span thereis a counter weight. The procedure for attacking this bridge is the sameas for a continuous bridge except the counter-weight would be droppedin lieu of severing an anchor span.
Fig 5-3-32 Double leaf basculebridge
Fig 5-3-33 Single leaf basculebridge
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b. Examination of Fig 5-3-33 shows that this older design is merely asingle span bridge and it is attacked accordingly.
5-3-45. Vertical Lift Bridge.The vertical lift bridge (right) caneasily be recognized as a singlespan and can be attackedaccordingly. As with the swingbridge, it may be desirable to denythe use of lift bridges by openingthe bridge and destroying theoperating mechanism.
Fig 5-3-34 Vertical lift bridge
PIERS AND ABUTMENTS.
5-3-46. Abutments. The demolition of bridge abutments as a means of causingcollapse of the bridge deck is unlikely to prove effective as an obstacle since thedeck structure will probably settle onto the debris of the demolished abutment andremain spanning the gap. Abutment demolition is only useful to increase thewidth of a gap created by demolition of the bridge and are most easily destroyedby buried charges which are described in Chapter 6.
5-3-47. Piers. The destruction of piers is the lowest priority task whendesigning a bridge demolition. Masonry and unreinforced concrete piers may bedestroyed by means of breaching or borehole charges, or by cutting chargesprovided the piers are not too thick and there is no shortage of explosives. Largereinforced concrete piers are best attacked by means of borehole charges, perhapsusing conical shaped charges. The demolition of piers shall be planned so as toleave nothing that might assist rebuilding.
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SECTION 4RAILROADS, AIRFIELDS AND PORTS
GENERAL
5-4-1. Transportation systems and facilities, such as roads, railroads, airfieldsand ports are essential to provide logistic support to a military force. In manyinstances, their capture is the objective of an operation. It is therefore importantthat engineers be prepared to deny the use of these facilities to the opposing forceif it appears they may be captured. Engineers shall also be prepared to rapidlyclear and open transportation facilities that the friendly force captures. Annex Cprovides a summary of the priorities of attack for the denial of airfields, ports andrailroads, and the principles explained in Section 6 shall be followed. Thedestruction of roads and bridges is explained in Sections 2 and 3 to this chapter.
RAILROADS
5-4-2. General. The most vulnerable points along a railway are the bridgesand tunnels. The method of attacking tunnels is described in Section 2, and bridgedemolition is described in Section 3.
5-4-3. Targets. In order for railway track destruction to be effective, it mustextend over a considerable distance because if spare rails are available, it can berepaired quickly. The location of rail damage should be sited where repair will bedifficult, such as on causeways or at side-hill locations. In rail systems, switchesare used to direct traffic to the various tracks. Their destruction will disrupt railtraffic and prevent the use of a rail marshalling area. Other targets for denial ordestruction are: the roadbed, rolling stock, communications and other facilities.
5-4-4. Tracks. In order to derail a train, it is necessary to remove about 6 mof straight rail or 3 m on the outside of a curve. Railway lines are mosteconomically destroyed using a cutting charge (Fig 6-2-3) at each alternate railjoint, thus damaging every rail at one end. If time is short, specialized locationssuch as points, crossings and curved rails shall be attacked. Side-hill cuts are alsoexcellent cratering targets.
5-4-5. Switches. Switches are specially fabricated devices that are not easilyreplaced because they include two specially machined components. If the switchrail and the frog (Fig 6-2-3) can be destroyed, the switch cannot be used.
5-4-6. Roadbed. If possible, destruction of the roadbed shall also beconsidered when attacking a railway. The same principles and methods of a roaddemolition apply.
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5-4-7. Locomotives. Serviceable locomotives and associated equipment areto be prevented from becoming usable to the enemy. Steam locomotives may beseverely damaged by the use of explosives to destroy the boiler, fire box,smokebox and attached cylinders, valve mechanisms and driving wheels. Diesellocomotives may be attacked along similar lines, the cylinder block and injectors,pumps, and similar ancillary equipment being removed or damaged. Althoughelectric locomotives can be similarly damaged, electrified systems are bestattacked at the power source and by destroying overhead power supply lines.
5-4-8. Communications. Disruption of communications including signals,telephone, telegraph, block instruments, and signal cabins prevents the operationof all but the most basic of services. Although explosives can be used effectively,destruction by sledge-hammer, small arms fire or burning should be considered.
5-4-9. Workshop facilities. Where time permits, all machinery shall beimmobilized by the removal of vital parts, or by the destruction of driving motorsand power supply.
5-4-10. Key personnel and records. The removal of key personnel andtechnical records is of great importance since their capture can provide aconsiderable advantage in the re-opening of rail facilities. Every effort should bemade to utilize the expertise and recommendations of railway technicians inplanning and executing demolitions on railway systems.
AIRFIELDS PRIORITIES
5-4-11. The priority of targets on airfields are the aircraft operating surfaces,the runway lighting systems and communication facilities.
a. The aircraft operating surfaces includes runways, taxiways and anyother areas which aircraft might use, even temporarily, for landing ortake-off. The road system around many permanent military airfieldsalso doubles as an emergency aircraft operating surface. All possiblerunways, regardless of orientation will be destroyed or denied.
b. Communications and operations facilities which will be destroyed arethe operations centre, control tower, radios, telephone switchboards,radio masts, relay and rebroadcast centres, antennas, radars andbeacons.
5-4-12. If time is available, the following additional targets shall be considered,in order of priority:
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a. Road System. Roads shall be destroyed at all approaches to theairfield in order to delay the arrival of repair equipment and material;
b. Fuel Facilities. Refuelling apparatus and tanks shall be destroyed.Fuel shall be burned or removed;
c. Utilities. Base utilities shall be destroyed or rendered inoperable,including electrical generating and distribution systems, water supplypumps, storage tanks and distribution systems, heating and coolingsystems, and sewage systems;
d. Engineer Resources. Material which may be used for the repair of theairfield shall be denied by removal, fire, demolition, or booby-trapping;
e. Workshops and Hangers. Aircraft maintenance equipment andmachinery shall be removed or destroyed and the buildings shall bedemolished. Hardened aircraft shelters shall also be destroyed; and
f. Administrative buildings.
METHOD OF AIRFIELD ATTACK
5-4-13. Effective airfield denial requires a clear definition of the aim; whetherthe airfield is to be denied or destroyed, and will be balanced against time andresources available and the requirement to conceal the denial. Destruction of theairfield and facilities by use of explosives and fire will warn the enemy of theairfield denial.
5-4-14. The quickest method to deny the use of the aircraft operating surfaces isto place obstructions or surface laid mines on it. Possible obstructions includevehicles, 45 gallon drums, tetrahedrons, debris, trees or wire.
5-4-15. The quickest method of destroying the runway is by ripping the surfaceto the extent that it is not trafficable. However, in most cases the surface is thickor even reinforced concrete and the task might be beyond the abilities of theripping equipment. Ripping alone may simply disrupt the running surface but notnecessarily making it unusable and hence easily repairable. Therefore, cratersshall be blown in addition to nuisance minelaying. Charge calculations for cratersare discussed in Chapter 6. In wet conditions, the destruction or blockage of thedrainage system may render the airfield inoperable, and can cause great delays inreconstruction.
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5-4-16. Obstructions should be spaced at no less than half the length of therunway, and extending across its full width, however the minimum aircraftoperating surface required by enemy aircraft shall be taken into consideration.Rows of craters are very effective, and even more so if placed across the runwayat intersections with taxiways. Once the essential minimum effective damage hasbeen done to the runways, similar methods can be extended to the remainingareas, including taxiways and roads on which landing or take-off might bepossible.
PORT AND INLAND WATERWAYS
5-4-17. The denial of port facilities may be either short or long term. Shortterm denial involves:
a. the removal of water craft, and material handling equipment, as well asessential parts of machinery;
b. the partial destruction of power sources;
c. denial of buildings and workshop facilities by the use of mines andbooby-traps; and
d. the blockage of transportation facilities.
5-4-18. The long term denial of ports includes the complete destruction of:
a. water, fuel and power facilities;
b. quays and jetties by craters or buried charges;
c. dry docks, locks and lock gates; and
d. cargo handling equipment such as cranes which can by tipped into thedock by cutting the legs nearest the water.
5-4-19. Inland waterways can be denied by:
a. the destruction of locks, dams, weirs and sluices and their relatedmachinery and pumping equipment;
b. the destruction of navigation aids; and
c. blocking by sinking barges and tugs and the destruction of bridgeswhich cross it.
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SECTION 5PEACETIME PREPARED OBSTACLES
GENERAL
5-5-1. Peacetime Prepared Obstacles are obstacles which are designed andconstructed in peacetime, designed for rapid execution in times of conflict. Theyare obstacles that are efficient in time, labour and material to execute, and limitdamage to a level required for the maximum effectiveness of the barrier. Theseobstacles may also be mined after execution to enhance their effectiveness.
5-5-2. Storage of the explosives is usually close to the target. Vehicles arerequired to transport stores and accessories to the obstacle site.
ROAD CRATER
5-5-3. Road craters areformed by the demolition ofprepared demolition shafts(measle) constructed into theroad systems which are 4 to 6 mdeep and 0.6 m in diameter.Upon removing the shaft cover,loading poles are used to lowerthe required number of 25 kgcharges into the shafts. Twounderground conduits areinstalled from the shafts to acovered box in the road
Fig 5-5-1 Demolition shafts
embankment for the firing circuit. This allows normal road traffic to continueeven when the firing circuits are in place. It consists of one group of three cratersand requires 60 to 90 minutes for a field section to prepare the demolition.
5-5-4. The craters which are formed interrupt the entire width of the road.Each crater is separated by 1 to 6 m wide area of intact roadway in order to avoida crater running longitudinally along the traffic facility.
BRIDGE DEMOLITION FIXTURES
5-5-5. Demolition fixtures in bridges allow for the rapid preparation of bridgetargets and effect considerable economies in labour and material as well as timecompared to normal demolition procedures. These fixtures may consist of chargemounting brackets, charge containers, charge chambers, demolition
5-5-6. Demolition fixtures and accessories facilitate easy loading andpreparation of the firing circuit. These fixtures and accessories can be installedpermanently, or under certain conditions, stored together with the explosives andexplosive accessories.
TUBE EXPLOSIVE DITCH OBSTACLE
5-5-7. Tube explosive ditch obstacles are prepared by installation of tubes ofexplosives (liquid, solid or gas) at predetermined depths in roads. Applicationsare comparable with road crater systems and their advantages are that they requireless explosives, are camouflaged due to the buried emplacement of the tubes, andare more cost effective in terms of installation and maintenance.
5-5-8. These obstacles form ditches which interrupt the entire width of theroad. As ditches will run in an angular direction to the road axis, it will becomemore difficult to negotiate by means of armoured vehicle launched bridges.
THRESHOLD OBSTACLE
5-5-9. Roads designed as peacetime prepared obstacles can have metal basketsbuilt into the drainage channels of the road. These metal baskets are designed tohold shaped or cutting charges. When the obstacle plan is implemented, theobstacle is prepared by placing the charges in the baskets and arming them. Thecharges are normally command detonated when the target vehicle is directly overthe obstacle, but modern sensors and fuzes may be incorporated. The thresholdobstacle is particularly suitable for reinforcing other obstacles.
FRAGMENTATION OBSTACLE
5-5-10. A fragmentation obstacle is an obstacle created by fixing explosivecharges to the outside of guardrails on one or both sides of a road.Premanufatured shaped charge containers with 40 kg of explosives are fixed to theexterior of the guardrails. The fragments formed when the charge is detonatedwill result in a mobility kill or a complete kill of the vehicle (including main battletanks) up to a range of 7 m.
5-5-11. The existing guard rail (3 mm thick) is replaced by a specially designed(8 mm) one. The charges are fixed to the fasteners on the outside surface. If nosensor or special fuze is used, the charges are command detonated when the targetvehicle is in line with the charge.
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MINE CHAMBER OBSTACLES
5-5-12. Mine chamber obstacles are emplaced in traffic facilities and consist offoundations, individual mine chambers and obstacle accessories.
BEAM POST OBSTACLE
5-5-13. The beam post obstacle is designed for blocking roads at defileswithout destruction of the pavement. A beam post obstacle consists of threedouble rows of beams over the entire width of the road surface. The beamreceptacles are built into the road foundation, flush with the surface, into whichthe special alloy metal I-beams are inserted. Each beam has a locking flap whichlocks the beam into position once placed into the receptacle. During training andexercises, the end of the I-beam with the locking flap is not placed into thereceptacle. When installed, the beams extend 1.4 m above ground and areimpossible for the enemy to pull out. The obstacle consists of the following: baseslab, beam receptacles (shafts), I-beam posts (2.2 m long), barrier accessories(camouflage nets, concertina wire), and obstacle accessories (carrying tongs,lifting hooks).
5-5-14. This obstacle is effectiveagainst all types of vehicles. Tobreach this obstacle, the beams mustbe removed and due to the designand type of material, this isextremely difficult. The barrieraccessories are placed on theopposing force side to make it hardto see the depth of the obstacle. Theobstacle may be reinforced withmines, off route mines and othertypes of obstacles. It will require Fig 5-5-2 Beam post obstacle
one section one hour to complete to install the stores and accessories.
FALLING BLOCK OBSTACLE
5-5-15. A falling block obstacle consists of one or two falling reinforcedconcrete blocks mounted on a concrete stand and foundation as well as ademolition beam and steel tube encased in concrete. Placed in an upright positionnext to a defile, the concrete blocks fall to the ground after the anchoring systemhas been cut by demolition. The falling block obstacle is designed for the rapidclosing of defiles without damaging the road surface. The falling block obstacle is
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suited for areas where it can be inconspicuously integrated into special terrain,existing cultural build-up or the traffic infrastructure such as a tunnel entrance.
5-5-16. The obstacle width ofone falling block will be up to 15m and up to 28 m when using twofalling blocks. The falling blockobstacle is activated by explosivedemolition of the beam supportingthe falling block by three sectionsof Bangalore torpedo.
AQUEOUS FOAM OBSTACLE
5-5-17. Aqueous foamobstacles are used as barriersagainst vehicles and foot soldiers,in tunnels of at least 100 m inlength. They may be employed asan independent obstacle or as abarrier reinforce-ment incombination with other
Fig 5-5-3 Falling block obstacle
types of obstacles. Aqueous foams use the oxygen out of the surrounding air inorder to form. The following equipment is required for preparing a foam obstacle:
a. high expansion foam generator;
b. foaming agent;
c. water supply in the vicinity of the barrier;
d. water hoses; and
e. wooden structure with foil lining for closing the tunnel openings, ifrequired.
5-5-18. The resulting lack of oxygen creates stalled engines and personneldisorientation and respiratory distress. Even in the case of frost, the foam can beproduced and the obstacle will still be effective.
5-5-19. The foaming agent and accessories are usually stored in the immediatevicinity of the site. The preparation time for one field section is approximately 30minutes and the obstacle is effective for 72 hours. By repeating the process
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periodically (at 12 hour intervals), the effectiveness will be maintained. Thisobstacle is not effective against rail locomotives.
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SECTION 6DENIAL OPERATIONS
GENERAL
5-6-1. Definitions. Denial operations are intended to deny the enemy the useof equipment, stores and facilities left behind after a withdrawal. This aim may beachieved by damage, removal, contamination, destruction or booby-trapping. Theauthority to order denial operations and to define their scope is usually retained ata high level because of the social and political implications and the effect theycould have on our own forces when the offensive is resumed.
5-6-2. The aim of denial operations is not so much to destroy completely, as tostop production or to prevent the use of the facility. To achieve this, targetselection and method of attack are critical. The aim must be balanced against timeand resources available and the requirement to conceal the denial. Denial byexplosives or fire will provide warning to the enemy of the denial operation andwithdrawal.
5-6-3. Scope. While this manual deals only with demolitions usingexplosives, other methods can be effective and may be more efficient in time andmaterials. Examples are:
a. fire;
b. water damage or flooding;
c. contamination of materials, fuels and lubricants;
d. inducing self-destruction (overloading, lack of lubrication etc);
e. removal of vital parts and machinery or personnel;
f. weapons fire; and
g. mines and booby-traps, provided authority has been issued by theauthorized commander for the booby-traps.
5-6-4. Expert Advice. Whenever possible, advice shall be sought fromcivilian technicians with specialist knowledge of the industry. Similarly, theremoval of key personnel and technical records is of great importance since theircapture could provide a considerable advantage in the re-opening of certainfacilities.
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TARGETS
5-6-5. Denial targets include:
a. transportation systems such as roads, airfields, railroads, ports andinland waterways;
b. industrial facilities such as factories, oilfields and refineries, mills,mines, and quarries;
c. untilities such as power generating stations, water facilities, sewagetreatment, and gas lines;
d. communications facilities and equipment such as telephone, radio,television, and satellites;
e. ammunition and explosives; and
f. accommodation facilities which could be used for troopaccommodation, storage or workshops.
5-6-6. The destruction and denial of roads, airfields, railroads and ports iscovered in Sections 2, 3 and 4 of this chapter. Annex C to this chapter provides asummary of priorities for denial operations.
INDUSTRIAL DENIAL
5-6-7. The aim of industrial demolitions is not to destroy the targetcompletely, but to stop production, or to deny the use of a facility such as a port.Correct target selection is of utmost importance. For continued operation,industry and utilities rely on transportation systems, electric power and fuel. Ofthese, electric power is the most vulnerable. A few well conceived attacks mayachieve widespread paralysis.
5-6-8. Industrial demolition techniques are guided by the following principles:
a. destroy machinery specially made for an installation;
b. destroy the source of power;
c. prevent cannibalization by attacking the same part on all equipment;and
d. destroy transportation systems.
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5-6-9. Mines. Mines can be effectively denied by destroying the mechanicalmachinery such as pumps at the bottom of "wet" mines, ventilating fans,conveyors, crushers, extractors, winding drums and the steam engines or electricmotors driving them, large special-purpose equipments or machines which will bediffficult to replace or install.
5-6-10. Mills. Steel mills can be denied by destroying the power source,exhaust and cooling water pumps, furnaces, centrifugal blowers, extractor pumpsto remove the furnace gas, and transportation and material handling equipment.
ELECTRICAL POWER SYSTEM
5-6-11. Components. The system of supplying electricity to industry consistsof: power generating stations, substations, the distribution lines, and the electricalmachinery at the factories.
a. Power stations. The major items of equipment consist of boilers andsteam turbines, diesel engines, water turbines and control gear, thegenerators, and substations containing step-up transformers andswitching gear for passing on the electricity to the distribution system.Most of this machinery is unique to each power station and would takea long time, possibly years, to replace;
b. Distribution system. The two chief components are overhead lineswhich are not difficult to replace, or underground cables which aredifficult to locate, and secondary substations containing transformers.The distribution system is generally interconnected, so that industry isnot solely dependent upon any one power station;
c. Factories. Factories contain transformers and electric motors.Important factories are connected to two or more sources of supply orgenerate their own power and may therefore be independent in thisrespect. Most factories are provided with a stand-by plant.
5-6-12. Area to Attack. Since the aim of attacking electricity sources is theinterruption of industry, the following principles shall be observed:
a. if a single factory, or a specific group of factories is to be denied, itwould require less effort to atack the factory or factories than theelectrical supply;
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B-GL-361-008/FP-003 175
b. if industry over a wide area is to be interrupted, it may be best to attackthe power stations. Stand-by facilities for individual factories or groupsof factories may have to be destroyed as well;
c. in attacking power stations, all those supplying an area shall beeliminated simultaneously; and
d. the distribution system is the least promising target because effectiveinterruption requires extensive damage throughout the area.
WATER SUPPLY
5-6-13. Most water supply systems include a treatment and storage facility suchas tanks or a reservoir, pumps, valves, a control system and a distribution system.Denial targets and methods are:
a. the pumps, valves and control system are the most vulnerable points ofattack and are usually located in one central pumphouse;
b. earth-walled reservoirs are best destroyed by buried charges placed inthe walls;.
c. water tanks may be destroyed by non-explosive means or by small armsfire. If explosives are used, 1 kg of plastic explosive per 6 m3 watercapacity of the tank, fired inside it when full of water will be sufficient;and
d. pipelines, if unburied, are simple to demolish. Junctions and bends arethe most suitable points to attack. Charges are placed at alternatejoints. Lengths of buried pipeline may be destroyed by running off thewater and firing a charge of explosive within them, or by digging themup and smashing them by hand. However, the damage that can beinflicted seldom justifies the effort required.
5-6-14. Wells. In some cases, it is preferable to conceal the well by filling it inand disguising the surface, rather than to draw attention to the site by an obviousdemolition. Other denial measures include:
a. wells sunk in shifting or unstable soils may be damaged beyond repairby cutting the lining. If time permits, the well should be filled withearth before firing the charges;
b. wells in hard soil or rock having little or no lining are best destroyed byexploding a buried charge, sufficient to create a 5 to 10 m diameter
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176 B-GL-361-008/FP-003
crater, at a depth 2 to 6 m and about 3 m from the edge of the well.This will obliterate the exact location of the well. Logs, machinery, orany bulky item at hand can be thrown down the well before firing thecharge. In a heavily shelled area it may often be advisable to use asmaller charge at a lesser depth, in order that the crater formed maypass for an ordinary shell-hole; and
c. deep boreholes may be destroyed by firing a 1 kg charge in the lining ata considerable depth below the surface, but above the natural waterlevel.
DAMS
5-6-15. For demolition purposes, dams may be divided into three main types:masonry or concrete gravity dams, multiple arch dams, and earth fill dams.
5-6-16. Masonry or concrete gravity dams (Fig 5-6-1). Gravity dams arebest destroyed by detonating a large breaching charge or charges underwater incontact with the face of the dam.
5-6-17. Multiple arch dams have very thin arches of reinforced concrete, thegreatest thickness of any arch known being less than 1.80 m. A large breach in anarch can be effected by lowering a charge down the water face so that it rests incontact with the arch either at the crown or at the haunch. Whenever possible,several arches shall be attacked simultaneously. Every effort will be made toensure as close a contact as possible is made between the explosive and the arch.The lowest part of some arches in certain dams have been filled with masonry. Ifthese dams
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are attacked, if possible an unfilledarch should be chosen or the chargeplaced so that it is above the level ofthe filling.
5-6-18. Earth fill dams. In damspartly or wholly constructed of earthfill, it may be possible to ditch orcrater below the existing waterlineand thus allow the water itself toerode and destroy the dam.
Fig 5-6-1 Demolition of dams
COMMUNICATIONS FACILITIES AND EQUIPMENT
5-6-19. The destruction or removal of communications equipment to prevent itfalling into enemy hands is normally performed by communications personnel. Ingeneral, it is only during offensive operations, such as a patrol into hostileterritory, that this task is completed by engineer demolition parties. If possibleone or more lineman and electricians are to be attached to the demolition party.
5-6-20. Telephone exchanges are the most vulnerable parts. Computer,instruments, batteries, exchange boards and automated switching equipment shallbe removed or smashed, and wires cut and tangled together. Main telephonecables are cut where they enter the building or just outside the building if they canbe exposed. All papers and records of messages should be preserved andforwarded through intelligence channels.
5-6-21. Lines may be destroyed by felling the poles, cutting all the wires orcables at intervals, and twisting them so as to render them useless. The poles shallbe cut about half-way along their length so they are too short for use in therepaired line. If possible, use locations where mobile line laying equipment is notemployable. Microwave relay towers shall be destroyed in a manner similar to thetelephone poles. Antenna dishes shall be destroyed or removed. Satellitetransceiver centres shall be destroyed by means similar to telephone exchangesand the antenna dishes destroyed or removed
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AMMUNITION AND EXPLOSIVES
5-6-22. The primary denial measure to prevent ammunition and explosivesfrom falling into the hands of the enemy is removal. The denial of ammunitionand explosives by detonation or burning is not to be confused with the destructionof munitions during battlefield munition or explosive ordnance disposal.
5-6-23. Detonation. The shells and bombs may be detonated as described inChapter 3. The detonation of one of a group of shells placed in close contact withanother is sufficient to fire the group if the filling is TNT. Where there is anydoubt on the filling, the advice of qualified personnel is required.
5-6-24. Burning. High explosives may often be destroyed by burning, but ifthe fire becomes too fierce, the remaining explosive may detonate. Gasoline,kerosene or diesel will assist combustion. Some forms of high explosive will notburn, especially if wet. The charge in such cases is best rendered harmless byscattering it over the ground. Waste explosive shall not be thrown into ponds ordown wells as it may poison the water.
5-6-25. Small Arms Ammunition. Small arms ammunition boxes shall bestacked in close contact, soaked with gasoline or kerosene, and ignited.Explosives cannot be used effectively to destroy small arms ammunition.
.
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ANNEX AMETHODS OF ATTACK SIMPLY SUPPORTED BRIDGES
Ser Sub-category Type Method of attack Remarks(a) (b) (c) (d) (e)1 Steel beam Through bridge I Lc
Top attack 1. Cut at mid-span 2. Cut beams including bottom flange in "V" 3. Deck need NOT be cut
2 Steel beam Through bridge II Bottom attack E is greater than ER
H.75 H
1. Cut at mid-span to depth 0.75 H as shown 2. Deck must be cut across full width of bridge
3 Steel beam Through bridge III Angled attack
1. Cut between 1/3 span and mid-span 2. Cut angle at approx 70° to beam flange 3. Deck must be cut across full width of bridge
End clearance is NOT a consideration
4 Steel beam Through bridge IV Bottom Attack E is less than ER
1. Cut at mid-span to depth 0.75 H as shown in Ser 2 2. Deck must be cut across full width of bridge 3. Attack the end of the bridge or one pier/abutment to create
sufficient end clearance
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Ser Sub-category Type Method of attack Remarks(a) (b) (c) (d) (e)5 Steel beam Through bridge V
(Where deck is locatedwell above the level ofthe bottom of the beams)
Top Attack E is less than ER
Lc
1. Cut at mid-span2. Use cuts as shown3. Deck need NOT be cut
6 Steel beam Deck bridge top support
Angled attack
1. Cut between 1/3 span and mid-span2. Cut entire beam at approximately 70° to beam flange3. Deck must be cut across full width of bridge
1. Found in cantilever and suspended spanbridges
2. End clearance is NOT a consideration
7 Steel beam Deck bridge bottom support I
Bottom attack E is greater than ER
1. Cut at mid-span 2. Cut full depth of web and both flanges 3. Deck need NOT be cut
8 Steel beam Deck bridge bottom support II
Bottom attack E is less than ER
1. Cut at mid-span 2. Cut full depth of web and both flanges3. Attack the end of the bridge or one abutment/pier to createsufficient end clearance 4. Deck need NOT be cut
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Ser Sub-category Type Method of attack Remarks(a) (b) (c) (d) (e)9 Steel beam Deck bridge bottom
support III Angled attack
1. Cut between 1/3 span and mid-span 2. Cut entire beam at approximately 70° to beam flange 3. Deck must be cut across full width of bridge
End clearance is NOT a consideration
10 Steel truss Through bridge I Top attack E is less than ERL c
1. Cut at mid-span 2. Cut top chord twice, vertical (if necessary), diagonal and bottom
chord 3. Wind bracing at top chord level must be removed over LC 4. Deck need NOT be cut
11 Steel truss Through bridge II Angled attack
1. Cut between 1/3 span and mid-span 2. Cut top chord, diagonals and bottom chord in one bay only. Cut is
to be angled at 70° to top chord 3. Deck must be cut across full width of bridge
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Ser Sub-category Type Method of attack Remarks(a) (b) (c) (d) (e)12 Steel truss Deck bridge top
support Bottom attack
1. Cut at mid-span 2. Cut top chord, diagonals and bottom chord in one bay only 3. Deck need NOT be cut
13 Steel truss Deck bridge bottom support I
Bottom attack E is greater than ER
1. Cut at mid-span 2. Cut top chord, diagonals and bottom chord in one bay only 3. Deck need NOT be cut
14 Steel truss Deck bridge bottom support II
Bottom attack E is Less than ER
1. Cut at mid-span2. Cut top chord, diagonals and bottom chord in one bay only3. Attack the end of the bridge or one pier/abutment to createsufficient end clearance4. Deck need NOT be cut
15 Steel truss Deck bridge bottom support III
Angled attack
1. Cut between 1/3 span and mid-span2. Cut angled at approximately 70° to top chord3. Deck must be cut across full width of bridge4. Cut top chord diagonals and bottom chord in one bay only
End clearance is NOT a consideration
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Ser Sub-category Type Method of attack Remarks(a) (b) (c) (d) (e)16 Concrete Through bridge Bottom attack
1. Cut at mid-span2. Complete cut through beam3. Deck must be cut across full width of bridge
17 Concrete Deck bridge topsupport
Top attackLc
Attack at mid-span using concrete stripping charge
1. Found in cantilever and suspended spanbridges
2. Remove concrete over length LC to fullwidth and depth of beams
18 Concrete Deck bridge bottomsupport
Bottom attack, E is greater than ER
Cut at mid-span
1. Applies to slab bridges only 2. This cuts sufficient rein-forcing bars in
reinforced concrete slabs to causecollapse
19 Concrete Deck bridge bottomsupport II
Bottom attack E is less than ER1. Cut at mid-span2. Attack the end of the bridge or one pier/abutment to create
sufficient end clearance
1. Applies to slab bridges only2. Same as above
20 Concrete Deck bridge bottomsupport III
Top attack E is less than ER
Attack at mid span using concrete stripping charge
Remove concrete over length LC to fullwidth and depth of beams. Plan for a twostage attack to cut the anchor span althoughfailure may occur after the first stage.
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Ser Sub-category Type Method of attack Remarks(a) (b) (c) (d) (e)21 Bowstring Normal Top attack
1. Cut at mid-span2. Cut bow in two places3. Cut any hangers between bow cuts4. Deck need NOT be cut
22 Bowstring Reinforced Top attack plus girders
1. Cut at mid-span2. Cut bow in two places3. Cut any hangers between bow cuts4. Deck need NOT be cut5. Cut longitudinal reinforcing beams/trusses as shown
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ANNEX BMETHODS OF ATTACK CONTINUOUS BRIDGES
Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)1 Concrete Cantilever Two complete cuts
SHEAR JOINT
1. Cut anchor span as near pier as practical 2. Cut mid-span shear joint
1. Plan for a two stage attack to cut the anchor spanalthough failure may occur after the first stage.
2. Use concrete stripping charge for first stage.
2 Concrete Cantilever and suspended span
One complete cut
1. Cut anchor span as near pier as practical
Plan for a two stage attack to cut the anchor spanalthough failure may occur after the first stage. Useconcrete stripping charge for first stage. Ifdemolition of the suspended span alone will createthe desired obstacle, regard the suspended span as asimply supported bridge, then categorize and attackaccordingly
3 Concrete Beam/truss withshort side span
One complete cutX Y
1. Cut interior span so that Y is greater than 1.25X 2. If necessary cut other interior spans as in Ser 4
Plan for a two stage attack to cut the longer spanalthough failure may occur after the first stage. Useconcrete stripping charge for first stage
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)4 Concrete Beam/truss,
without short span Two or more complete cuts
X Y X Y
Cut spans so that Y is greater than 1.25X
Plan for a two stage attack although failure may occurafter the first stage. Use concrete stripping charge toachieve first stage.
5 Concrete Portal, fixedfooting
Two complete cuts
Cut span twice close to piers
Plan for a two stage attack although failure mayoccur after the first stage. Use concrete strippingcharge to achieve first stage.
6 Concrete Portal, pinnedfooting
Stripping of ConcreteLc
L c
Remove concrete from mid-span over length Lc using concretestripping charge
1. Plan for a two stage attack although failure mayoccur after the first stage.
2. When footing conditions are unknown, method ofattack must be as for Ser 5
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)7 Concrete Arch, open
spandrel, fixedfooting I
Stripping of ConcreteLc
1. Remove concrete over length Lc, using concrete stripping charge
1. This applies to arches of span greater than 40 monly.
2. Plan for a two stage attack although failure mayoccur after the first stage.
8 Concrete Arch, openspandrel, fixedfooting II
Stripping of Concrete
Lc
Springing Line
1. Remove concrete from midspan over length Lc using concretestripping charge formula2. Attack Springing Line against top face of arch ring
1. This applies to arches of span less than 40 m.2. Plan for a two stage attack to cut the anchor
span although failure may occur after the firststage.
9 Concrete Arch, openspandrel, fixedfooting III
Four complete cuts 1. This method is an alternative to Serial 8 andapplies to arches of span less than 40 m
2. Plan for a two stage attack although failure mayoccur after the first stage.
3. Use concrete stripping charge to achieve firststage
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)10 Concrete Arch, open
spandrel, pinnedfooting
Stripping of concrete
Lc
1. Remove all concrete over length Lc, using concrete stripping charge
Plan for a two stage attack although failure mayoccur after the first stage.
11 Concrete Arch, solidspandrel, fixedfooting I
Stripping of Concrete
Lc
Remove concrete from midspan over length Lc using concrete strippingcharge
1. This applies to arches of span less than 40 m2. Plan for a two stage attack although failure may
occur after the first stage.
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)12 Concrete Arch, solid
spandrel, fixedfooting II
Stripping of Concrete
Lc
Springing Points
1. Remove all concrete over length Lc2. Attack both springing points by removing concrete using concrete
stripping charges either:a. against bottom face of arch ring, orb. against top face of arch ring, having removed spandrel fill
beneath roadway.
1. This applies to arches of span less than 40 m2. Plan for a two stage attack although failure may
occur after the first stage.
13 Concrete Arch, solidspandrel, pinnedfooting
Stripping of concrete
Remove all concrete over length LC using the concrete stripping charge
Plan for a two stage attack although failure may occurafter the first stage.
14 Steel Cantilever Two complete cuts
Cut anchor span as near pier as practical1. Cut mid-span shear joint
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)15 Steel Cantilever and
suspended spanOne complete cut
Cut anchor span as near pier as practical
If the demolition of the suspended span alone willcreate the desired obstacle, regard the suspended spanas a simply supported bridge, and categorize andattack accordingly
16 Steel Beam/truss with short side span
One complete cut
.1. Cut interior span so that Y is greater than 1.25X 2. If necessary, cut other interior spans as in Ser 17
17 Steel Beam/truss without short side span
Two or more complete cuts
Cut interior spans so that Y is greater than 1.25X18 Steel Portal, fixed
footingTwo complete cuts
Cut span twice close to piers
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)19 Steel Portal, pinned
footingTwo complete cuts
Remove section from mid-span over length LC
When footing conditions are unknown, use themethod of attack in Ser 18.
20 Steel Arch, openspandrel, fixedfooting
Four complete cuts
21 Steel Arch, openspandrel, pinnedfooting
Two complete cuts
Remove section from mid-span over length LC
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Ser Sub-category Type Method Of Attack Remarks(a) (b) (c) (d) (e)22 Masonry
arch ITwo complete cuts
Cut at haunchesArch ring, spandrel walls and parapet shall all be attacked
23 Masonry,arch II
One complete cut
Breach arch ring at crown
Use this method as an alternative to Ser 22 only whentime is insufficient to allow attack at haunches
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ANNEX CPRIORITIES OF DENIAL OPERATIONS
Ser Equipment Priority Parts to attack1 Roads system 1
23
Destroy bridges and other crossing sitesCrater at defiles or crossroadsRip roads, or create abatis at defiles or crossroads
2 Airfields 1234
Destroy or deny all aircraft operating surfacesDestroy communications and operations equipmentDestroy fuel facilities and other utilitiesDestroy access roads, hangers and workshops, and engineer resources
3 Railroads 1234
Destroy railroad tracks and switches by using cutting chargesDestroy the roadbed by using cratering charges (in restricted areas)Remove or destroy locomotivesDestroy communications and workshop facilities
Ports Short term
1234
Remove watercraft, floating cranes, dredgers, etcPartially destroy power and clean water sourcesDestroy road and rail systemsRemove essential machinery parts
4
Long term 1234
Disrupt power stations servicing the portDestroy quays and jettiesDestroy dry docks, locks and lock gatesDestroy crane legs and supports so cranes will fall in the direction of the water
5 Inland waterways 123456
Create obstructions by sinking tugs and bargesRemove or destroy vital parts of locks and sluice gatesDestroy aqueducts by concussion chargesDestroy earth dams retaining water at a higher level than the surrounding areaDestroy road and rail bridges over waterwaysMine and booby-trap defiles and landing sites
6 Industrialfacilities,- (mechanical)
1234
Remove or destroy special machinery by explosives or inducing self-destructionDestroy power and water sourcesDestroy road and rail systemDestroy material handling equipment
7 Industrialfacilities -(electrical)
1234
Destroy or remove special electrical machineryDestroy stand-by power sourcesDestroy all power stations supplying the area to be deniedDestroy power distribution network supplying the area
8 Water supply:Pipes &storage
123
Destroy pumps, valves, and control systemDestroy reservoirs and holding tanksDestroy pipelines (joints and bends if accessible)
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Ser Equipment Priority Parts to attackWells 1
234
Block access to well by throwing machinery and agriculture implements down itCrater 3 m from the well to collapse and conceal the entranceDestroy deep wells by suspending charges above water lineDisconnect or destroy rising pipes and pump rods
9 Dams 12
3
Destroy masonry or concrete dams by submerging a breaching charge in contact with the faceDestroy multiple arch dams by submerging a breaching charge in contact with the crown or the haunch of the wall (If possible,several arches should be attacked simultaneously)Destroy earth filled dams by crating to below the water line
10 Communicationfacilities
1
2
Destroy computers, instruments, batteries, and exchange boards, within exchanges and central offices and in satellite transcieverstationsDestroy lines and relay sites by felling poles and towers, cutting near the centre so they cannot be re-used and in an area difficult formobile line laying equipment. Destroy or remove dish antennas
11 Ammunition andexplosives
12
345
Recover or remove munitionsStack shells in close contact and detonate as many exposed ones as possible. This will destroy or disperse the shells leaving anunsafe environment.Detonate explosives by normal meansStack small arms ammunition in boxes, soak with gasoline or kerosene, and igniteBurn explosives (gasoline or kerosene will assist combustion)
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CHAPTER 6
CHARGE CALCULATION AND PLACEMENT
SECTION 1
INTRODUCTION
GENERAL
6-1-1. Explosive charges can be used to cut/shatter, lift/heave, breach and stripa variety of targets. To ensure that the charge successfully detonates and themaximum effect is achieved, the following factors shall be considered:
a. Charge placement and close contact with the target.
b. The direction of initiation.
c. Tamping and stemming.
d. Correctly calculated charge quantities.
CLASSIFICATION OF CHARGES
6-1-2. It is convenient to classify explosive charges according to their uses indemolition tasks, as each charge has its own method of calculation andapplication. This chapter discusses the use, calculation and placement of thefollowing types of charges:
a. cutting charges.
b. breaching charges.
c. pier Footing.
d. borehole charges.
e. mined charges.
f. concussion charges.
6-1-3. These charges can be used against targets as indicated in the table atFig 6-1-1.
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6-1-4. Chapter 8 of this manual covers demolitions in an under waterenvironment and ice demolition charges. Underwater demolitions are alsodiscussed in B-GL-320-008/FP-001, Engineer Field Manual, Volume 8, CombatDiving. B-GL-320-009/FP-001, Engineer Field Manual, Volume 9, Demolition,Part 1, All Arms, discusses the use of explosives in construction tasks such asweapons pits and shelters. B-GL-320-012/ FP-004, Engineer Field Manual,Volume 12, Horizontal Construction, Part 4, Pits and Quarries, discussesquarrying and rock blasting.
6-1-5. Charge calculations in this publication are determined by the targettype, size and method to be used. Each target has an example calculation.Tabular answers, based on deliberate formulas, are attached as annexes to thischapter. The rule in charge calculation is to round up to the nearest quarter blockand when calculating charge end cross section (Cx), Cx will not be less than one.
6-1-6. In 1994, the dimensions of a block of C4 explosive were researchedand documented to alleviate any further discrepancies in calculations. They are asfollows:
a. Block length is 27.94 cm rounded to 28 cm.
b. Block width is 5.08 cm rounded to 5 cm.
c. Block thickness is 2.54 cm rounded to 2.5 cm.
d. Block weight is 0.558 kg rounded to 0.56 kg.
e. Block volume is 350 cm3.
6-1-7. Measurements in this manual are in centimetres (cm) or metres (m) andweights in kilograms (kg). All existing formulas have been recalculatedmathematically to be easier to work with.
6-1-8. Rounding off/up errors have always been a problem or point ofcontroversy in instruction and calculations. The simplest way to correct thisproblem is to create a common standard by adopting the following rules:
a. All calculations in a given formula shall be done in cm or m, and kg.
b. Rounding off to two decimal places shall be done at each step of acalculation.
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c. Conversion from kg to blocks of C4 is accomplished by dividinganswers in kg by 0.56 (the weight of a block of C4).
d. Then rounding up to the nearest quarter block.
e. All charge calculations are then totalled for the quantity of explosiverequired for the task. At the final stage (i.e. squadron level), the finalcharge quantity is calculated by adding an extra 10 % to compensate forcharge placement and waste.
FORMULA NOTATIONS
6-1-9. There are many symbols in the formulas used to calculate chargequantities. Depending on the target and the type of charge being calculated, it isvery critical that the correct symbol, method and chart is used.
Ser Symbol Meaning Unit ofmeasurement
(a) (b) (c) (d)1 A Area cm2 or m2
2 C Charge required kg or no of blocks3 CT Weight of tamping charge kg4 CW Weight of charge per m of bridge
beam or slab (concrete trippingcharges)
kg/m
5 Cx Charge end cross section block6 c Circumference cm7 D Depth cm or m8 d Diameter cm or m9 K Structural factor (concussion
charges)10 H Height cm or m11 L Length cm or m12 LC Minimum length of section to be
removed (Sheifield tudy)cm or m
13 LC Line or length of cut cm or m14 Lr Line of least resistance cm or m15 N Number of charges16 r Radius cm or m17 S Charge spacing cm or m18 T Thickness cm or m
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Ser Symbol Meaning Unit ofmeasurement
(a) (b) (c) (d)19 VOD Velocity of detonation m/s20 V Volume cm3 or m3
21 W Width cm or m22 Wd Width of ditch cm or m
Fig 6-1-2. List of formula notations.
EXPLOSIVE FACTORS
6-1-10. Explosives vary not only in their velocity of detonation (VOD), but alsoin other characteristics, such as density, brisance, power and energy output, whichcan affect their effectiveness for various demolition applications. The ExplosiveFactor is based upon the shattering effect, brisance, of an explosive in relation toC4 plastic explosive. The shattering effect of a high explosive is related to itsVOD. With cratering charges, the explosives ability to lift and heave is of greaterimportance than a high VOD. The system used in the past was the RelativeEffectiveness (RE) factor based upon the shattering effect of an explosive inrelation to TNT. For example, TNT was designated the standard 1.0 explosivebase line factor, and C4 was given a relative effectiveness factor of 1.34. Thesystem has been changed to C4 explosive as the standard 1.0 explosive base linefactor. Table 6-1-3 shows the explosive factors by which charge calculated in kgof C4 is multiplied in order to obtain the required amount of explosive.
Notes BE-Belgian,CA-Canada, FR-French, GE-German, US- American Manufactured
Fig 6-1-3. Explosive Factors.
CHARGE PLACEMENT
6-1-11. Charge placement is very important and must be emphasized in alldemolition work. Whatever the method of calculation adopted, the rules forplacing and affixing charges to targets are similar. These rules are explained bycharge type throughout this chapter.
6-1-12. If part of a target is inaccessible, it may not be possible to place acharge where it will produce the maximum effect. This limitation may make itnecessary to increase the size of the charge. Examples are described under thetargets to which they apply. The use of bolt guns could be replaced by wire, guntape or strapping material.
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SECTION 2
CUTTING CHARGES
USE
6-2-1. Cutting charges are usually the quickest to place because no tamping isnecessary, though sometimes they have to be placed in awkward positions. Theshattering effect of cutting charges produces desirable results against hardmaterials such as timber, steel, and concrete, but beyond certain thicknesses theiruse becomes uneconomical owing to the vastly increased amount of explosiverequired.
6-2-2. The following rules regarding charge calculation and placement shallbe observed to achieve the most effective results:
a. The charge must be continuous over the complete line of cut.
b. Close contact between the charge and target is essential. In the case ofuneven or irregular targets, such as riveted girders, plastic explosivesshall be used with the explosive moulded to the surface of the target soas to leave no air gaps.
c. The proportions of the charge end cross-section (Cx) shall be such thatthe width (W) is between one and three times the thickness (T). In anycase, charges more than 15 cm thick shall be avoided as better effect isobtained by increasing the width.
d. If a number of charges are utilized to make a single cut, ensure that theyall initiate simultaneously.
e. Boards or another form of packing shall be used to ensure that anystrapping does not cut into the explosive.
f. If charges are placed on both sides of the target, they shall be staggered,with a slight overlap not to exceed 0.3 cm, so that they have a scissoreffect. This rule does not apply to conical or linear-shaped charges.
g. For long linear charges, there shall be one initiation point every 1.5 m.
h. The direction of initiation shall be perpendicular to the target, with theinitiation point placed on the face of the charge opposite to the target.
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STEEL, RECTANGULAR STEEL SECTIONS
6-2-3. General The configuration of the steel in the structure will determinethe type and amount of explosive charge necessary. Examples of structured steelincludes I-beams, wide-flange beams, channels or steel plates used in bridge orbuilding construction.
6-2-4. Calculations. Charges for cutting rectangular structural steel sectionsare calculated using the following formulas:
Cx = T2 x length of block (cm) 380 weight of block (kg)andC = LC x Cx length of block
WhereCx = charge end cross sectionT = target thickness (cm)C = charge required (blocks of C4)LC= length of cut (cm)
a. Determine Cx using the formula given and round up to the nearestquarter block.
b. Cx is then multiplied by the length of cut divided by the length of ablock of explosive, and then rounded up to the nearest quarter block togive the total charge required (C).
c. For steel girders and universal steel beams, the charges for each part,i.e. the top flange, web and bottom flange, must be calculatedseparately. There may be rivet heads and angle pieces (joining theflange to the web) to contend with. In such cases, the flange thicknessis taken to be the maximum thickness over the whole width of theflange, i.e. the total thickness of one rivet head, plus plates, plus anglepiece. The thickness of the web is measured at its thinnest point, i.e.the plate ignoring rivet heads and angle pieces.
d. For lattice girders, the calculations for the flanges follow the same rulesas for the flanges of other beams and built up girders. The web latticeis cut by placing a charge of the required size on each lattice member,on the line of cut.
e. For steel rails, a charge of 0.5 kg of plastic explosive can normally cutthe heaviest rail, and create a gap of 0.5 m. If a fish-plate must be cutwith the rail, a charge of 0.75 kg of plastic explosive is required. SeeFig 6-2-3.
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f. Note: It is a recognizedfact that a unique situationexists in this formula suchthat the value of Cx shallnever be less than 1.
6-2-5. Example. Calculate thecharge required to cut the steel girderat the right using C4. Note that whencalculating steel cutting charges,each section is calculated separately.The following is an example inwhich the steel girder is treated asthree separate steel sections
a. Top Flange. T = 4.5cm, LC= 52.0 cm, lengthof block = 28.0 cm Fig 6-2-1 Calculations - cutting
charge for steel girder. (1) Cx = (4.5 cm)2 x 28 cm = 2.66 380 0.56 kg
rounded up to nearest 1/4 block, 2.75
(2) charge required C = LC x Cx length of block
= 52 cm x 2.75 = 5.11 28 cmrounded up to the nearest ¼ block = 5.25 blocks
b. Web. T = 2 cm, LC= 110 cm,
(1) Cx = (2 cm)2 x 28 cm = 0.53 380 0.56 kgrounded up to nearest ¼ block, = 0.75
Note: Cx must not be less than 1 therefore use 1
(2) charge required C= LC x Cx length of block
= 110 cm x 1.0 = 3.93 28 cm rounded up to nearest ¼ block 4.0 blocks
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c. Bottom Flange. T = 7.5 cm, LC= 65 cm,
(1) Cx = (7.5 cm)2 x 28 cm =7.40 380 0.56 kg rounded up to nearest ¼ block, = 7.50
(2) charge required C = LC x Cx length of block
= 65cm x 7.5 =17.41 28cm rounded up to nearest ¼ block = 17.5 blocks
d. Total explosives required for line of cut: C= 5.25 + 4.0 + 17.5 = 26.75 blocks.
6-2-6. Limitations. Linear shaped charges shall be used for rectangular steeltargets thicker than 12.3 cm.
6-2-7. Charge Placement. Fig 6-2-2 shows methods of placing charges whenvarious parts of the target are inaccessible. Except for the case shown in Fig 6-2-2(d), flange charges shall be off-set either side of web charges so as to avoidopposition-of-charge effects through the flanges. All charges shall be securedtightly against the target. There shall be no air space left between the explosiveand the target.
Fig 6-2-2 Charge placement for steel girder.Note s : 1. C1, C2, C3 = ch arge s for top flange , w e b and
bottom flange re s pe ctively.2. �≡ - initiation points and direction.3. (a) - both flanges accessible.4. (b) - top flange inaccessible.5. (c) - both flanges inaccessible.
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6. (d) - both flanges and one side of web inaccessible. (Flange charges are doubled, but will not completely
cut top flange if over 2.5 cm thick)
6-2-8. Tabular Answers. For tabular answers, see Annex A of this chapter.
Fig 6-2-3. Charge Placement for Steel Rail.
ROUND STEEL BARS, CABLES AND CHAINS
6-2-9. General. Round bars and cables are classified as either Mild Steel(MS), High Carbon Steel or Steel Wire Rope (SWR).
6-2-10. Calculations. The charge size is calculated using the formulas on thenext page:
a. Determine the charge weight by using the above formula. (Seelimitations at para 6-2-12.b. below.)
b. Divide the charge weight (kg) by the weight of explosives to be used, todetermine the amount of blocks required.
6-2-11. Example. Calculate the charge size (C4) required to cut a cable of 18.0cm circumference:
a. C= c2 = (18 cm)2 = 0.72 kg 450 450
b. C= 0.72 kg=1.29 rounded to 1.5 blocks of C4 0.56 kg
6-2-12. Limitations. The following limitations apply to cutting round steelbar, cables and chains:
a. The above calculation formulas give charge quantities for moststructural and cable steels up to 31.4 cm circumference (10.0 cm indiameter). For larger targets, the charge quantity required varies closerto the cube than the square of the diameter. This makes the normalcutting charge method uneconomical. In such cases, shaped chargesshall be used.
b. The above formulas can also be used against high carbon steel andalloy targets up to 15 cm in circumference. Once the charge per kg iscalculated, it is then multiplied by 2.5.
6-2-13. Charge Placement.
a. For bars over 23.0 cm, and cables over 22.0 cm in circumference, halfof the charge shall be placed on each side of the target and slightlyoverlapped not to exceed 0.3 cm, so as to produce the maximumshearing effect (see Fig 6-2-4).
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Fig 6-2-4 Charge Placement for a Steel Wire Rope of Circumference Greater than 22.0 cm.
b. For smaller targets, the charge is placed on one side. Charges must besecurely fastened, with as much surface area as possible in closecontact with the target .
c. The size of steel chain link varies making proper charge placementdifficult. Fig 6-2-5 shows charge placement for a chain. If theexplosive charge is long enough to bridge both sides of a link, or to fitsnugly between the two links, use one charge. If the explosive is notlarge enough to bridge both sides use two charges calculated as perround steel bar.
Fig 6-2-5. Charge Placement for Steel Chains.
6-2-14. Tabular Answers. For tabular answers, see Annex B of this chapter.
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SADDLE CHARGES
6-2-15. General. Saddle charges are used to cut round, or rectangular mildsteel targets up to 20 cm in thickness or diameter. The charge is a triangularshape (Fig 6-2-6), cut from a block of C4 or detasheet, with a uniform thickness of2.5 cm.
Fig 6-2-6 Saddle Charge.
6-2-16. Calculations. Charges are calculated using the followingformulae:
V = L x W x TC= ______V_________
Volume of explosives
Where V = Charge volumeL = Charge lengthW = Charge widthT = Charge thicknessC = Charge size in blocks or area of detasheet
a. charge length ( L ) is the targets circumference or thickness.
b. charge width ( W ) is one half the targets circumference or thickness.
c. charge thickness ( T ) is always 2.5 cm.
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d. charge volume ( V ) is L x W x T.e. Divide the charge volume by thevolume of explosive to be used such as C4 ( 350 cm3 ) or Detasheet (5833 cm3 ).
6-2-17. Example. Calculate, for C4, the size of saddle charge to cut a mildsteel bar 56 cm in circumference.
a. L = the circumference of the target = 56 cm.
b. W = half the circumference = 56 cm x .5 = 28 cm.
c. T = 2.5 cm.
d. V=L x W x T = 56 cm x 28 cm x 2.5 cm = 3920 cm3.
e. C = V ) volume of C4 = 3920 cm3 ) 350 cm3 = 11.2 or 11.25 blocks.
6-2-18. Limitations. The saddle charge can not be used on targets greater than20 cm thick.
6-2-19. Charge Placement. The following charge placement applies to thesaddle charge:
a Charge shall be initiated at apex end ( pointed end ) of the long axis.
b. The long axis of the charge shall be placed parallel with the long axis ofthe target.
c. The charge shall be securely taped to the target.
RECTANGULAR TIMBER
6-2-20. General. Cutting charges for timber may be used to destroy woodentrestles, bridges or timber structures, as well as land clearing. Timber cuttingcharges may be used effectively against large diameter targets, however they tendto be uneconomical in explosives required. Therefore, if time to prepare the targetis not critical, borehole charges (see Section 5) are more economical.
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6-2-21. Calculation. Charges for cutting rectangular timber are calculatedusing the following formulas:
Cx = T2 x length of block(cm) 42,000 weight of block (kg)
C = LC(cm) x Cx length of block
whereCx = the charge end cross sectionT = the thickness of the target (cm)C = charge required (blocks of C4)LC = length of cut (cm)
a. Determine Cx by using the formula given and round up to the nearestquarter block.
b. Cx is then multiplied by the length of cut divided by the length of blockof explosive, and then rounded up to the nearest quarter block togive the total charge required (C).
c. It is a recognized fact that a unique situation exists in the formula thatthe value of Cx shall never be less than 1.
6-2-22. Example. Calculate the charge required to cut a rectangular timberpost measuring 50.0 cm wide by 60.0 cm thick using C4.
a. Cx = (60 cm)2 x 28 cm = 4.29 42,000 0.56 kg rounded up to the nearest ¼block, 4.50
b. charge required C = LC x Cx length of block = 50 cm x 4.50 = 8.04 rounded to 8.25 blocks 28 cm
6-2-23. Limitations. The following limitations apply when cutting rectangulartimber:
a. For timber thicker than 0.76 m cutting charges are uneconomical andborehole charges shall be used.
b. A method for cutting timber piles under water is shown at Figure 6-2-7and described in para 6-2-29.b. of this section.
6-2-24. Charge Placement. The charge must be placed in direct contact withthe target.
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6-2-25. Tabular Answers. For tabular answers, see Annex C of this chapter.
ROUND TIMBER/ABATTIS
6-2-26. General. Due to the variety of wood types, the calculated charge sizeobtained from the formula in para 6-2-27 could have varying results. Treesgenerally rot from the core out which may not be visible, therefore test shots arehighly recommended.
6-2-27. Calculations. For cutting round timber the following formulas shall beused:
C(kg) = 32 x (c ÷ (100 π) )3
or C = 32 d3
WhereC = the total charge (kg or blocks)c = the circumference of the target (cm)π = pi = 3.14d = the diameter of the target (m)
a. Determine the charge weight by using the above formula.
b. Divide the charge weight (kg) by the weight of your explosives to beused, to determine the amount of blocks required.
c. The charge size suggested to create abatis, leaving the trees attached tothe stump, is 80% of the charge determined by the above calculation.
6-2-28. Example. Calculate the charge required to cut a piece of round timber87 cm in circumference using C4:
a. C(kg) = 32 (c ) (100 x π) )3
C(kg) = 32 (87 cm ) (100 x π) )3 = 0.68 kg
b. C(blocks) = total charge weight in kg weight of block in kg C(blocks)=0.68 kg=1.21 blocks rounded to 0.56 kg
1.25 blocks of C4
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6-2-29. Limitations. The following limitations apply when cutting roundtimber:
a. For timber thicker than 2.35 m in circumference cutting charges areuneconomical and borehole charges shall be used.
b. A method of cutting timber piles underwater is shown below. Thecharge is placed against the upstream side of the pile andnear the bottomto obtain the fulltamping effectof the water. Inthis case, thetamping com-pensates for anylack of closecontact betweenthe charge andthe pile. Plasticexplosives arenormally used.
Fig 6-2-7. Charge placement for timber piles......................................................
6-2-30. Charge Placement. On round timber, the charge must be placed inclose contact with the target. If the target is a tree, the bark must be removed andthe charge moulded to the same curvature of the tree to
ensure the close contact betweenthe explosive and solid wood. Ifthe tree is leaning the wrong way tothe desired direction of fall, or isaffected by a strong wind, a"kicker" charge of approxi-mately0.5 kg (1 block of C4) is placedtwo-thirds of the way up the tree onthe opposite side of the maincharge, and initiatedsimultaneously as shown at right
Fig 6-2-8. Charge placement for tree felling.
6-2-31. Tabular Answers. For tabular answers, see Annex D of this chapter.
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MASONRY AND UNREINFORCED CONCRETE
6-2-32. General. Cutting charges provide a quick and effective method ofattacking masonry, i.e. brickwork and stone-work, and unreinforced concretetargets. However, they are relatively expensive in explosives and shall not be usedfor targets thicker than 1.5 m. Although slow to prepare, borehole charges aremuch more economical and can be used effectively against larger targets.
6-2-33. Calculations. Charges for cutting masonry and unreinforced concreteparapet and spandrel walls, piers, and arch rings are calculated separately usingthe following formulas, and then added together to give a total charge required.
a. Walls:
CX =8 T2 x length of explosive (cm) 100 weight of explosive (kg)
C = CX x LC(cm) length of explosive (cm)
Where:CX = Charge end cross-sectionT = Wall thickness (m) C = Total charge quantity (blocks)LC = Length of cut (cm)
b. Piers:
CX = 32 T2 x length of explosive (cm) 300 weight of explosive (kg)
C = CX x LC(cm) length of explosive (cm)
Where:CX = Charge end cross-sectionT = Pier thickness (m) C = Total charge quantity (blocks)LC = Length of cut (cm)
c. Arch Rings:
CX=12 T2 x length of explosive (cm) 100 weight of explosive (kg)
C = CX x LC(cm) length of explosive (cm)
Where:CX = Charge end cross-sectionT = Wall thickness (m) C = Total charge quantity (blocks)LC = Length of cut (cm)
6-2-34. As a general rule in the calculations for masonry and unreinforcedwalls, piers and arch rings the following applies:
a. Determine CX using the formula given and round up to the nearestquarter block.
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b. CX is then multiplied by the length of cut required (LC divided by thelength of the block of explosive, and the answer is rounded up to thenearest quarter block to give the total charge required.
c. The value of CX shall never be less than 1.
6-2-35. Example. Calculate the charge required to cut an unreinforcedconcrete wall measuring 0.52 m thick and 2.1 m high, using C4.
a. CX = 8 T2 x length of explosive 100 weight of explosive
CX = 8 x (.52m)2m x 28 cm 100 0.56 kg
CX = 1.08, rounded up to 1.25 blocks of C4
b. C = CX x ____LC_____ length of block
C =1.25 x 210 cm 28 cm
C = 9.37, rounded up to 9.5 blocks of C4
6-2-36. Limitations. The only limitation which applies to cutting masonry andunreinforced concrete walls, piers and arch rings is that target depth/thicknessmust not exceed 1.5 m.
6-2-37. Charge Placement. The following rules apply:
a. Walls:
(1) Charges shall be placed along the bottom of the wall across thefull width of the desired cut.
(2) The width attacked must not be less than the height of the wall.
b. Piers:
(1) For solid piers, charges shall be placed along the bottom of thepier across its full width.
(2) For rubble filled piers, the filling will rarely be consolidated wellenough to transmit the detonation wave completely through thepier. Charges shall therefore be placed on opposite sides of thepier, slightly offset from each other, to produce a shearing effect.
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Each charge shall be one half of the total charge quantitycalculated and both charges must be initiated simultaneously.
c. Arch rings:
(1) Charges must be calculated to cut the full width of arch ring,including the position beneath the parapet walls. The spandreland parapet wall may also have to be cut, see Chapter 5, Section3.
(2) If the span is to be attacked from the top, then digging down tothe arch ring through the roadway and filling will be necessary.In this case, the portions of the arch ring beneath the spandrelwalls will be inaccessible; the charges calculated for thespandrel walls must be placed against the base of the spandrelwall at each end of the line of cut as shown in Fig 6-2-9.
(3) If the span is to be attacked from the bottom without removingthe filling from above the arch ring, the charge must beincreased to allow for the support given to the masonry by thefilling.
(a) If the filling is of solid concrete, its full thickness must beadded to the thickness on the arch ring when calculating thecharge.
(b) If the filling is well consolidated earth or rubble, topped byan aggregate pavement, one-half of the filling thickness mustbe added.
(c) When the filling consists of loose earth or rubble, only one-quarter of its thickness need be added.
(d) Skew arches. Considerations of economy of explosivesrequire the charge be at right angles to the centre line of thebridge; but this involves deeper trenches and some curvatureto the charge which might make it difficult to keep theexplosive blocks in close contact with each other, especiallywhen only one layer of blocks is required. With required.With arches of small radius or pronounced skew, it may benecessary to emplace the charge nearly parallel to the axis ofthe vault (see Fig 6-2-9), though in some cases anintermediate position may be found.
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Fig 6-2-9. Line of Cut.
6-2-38. Tabular Answers. For tabular answers see Annex E of this chapter.
REINFORCED CONCRETE
6-2-39. General. Cutting charges are an uneconomical method of attackingreinforced concrete; they are reliable only against small beams and slabs up to22.5 cm thick. An alternative method is to use a shaped charge, but all shapedcharges have their limits of performance. The methods of calculating normalcutting charges are set out below.
6-2-40. Calculations. Charges for cutting small reinforced concrete beams andslabs are calculated as follows:
a. Reinforced concrete slabs up to 22.5 cm thick.
CX = 3.2 T2 x length of explosive (cm) weight of explosive (kg)
C = CX x LC(m) Length of explosive (m)
Where:CX = Charge end cross-sectionT = Slab thickness (m)C = Total charge quantity (blocks)LC = Length of cut (m)
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b. Reinforced concrete beams up to 22.5 cm thick.
CX = 6.4 T2 x length of explosive (cm) weight of explosive (kg)
C = CX x LC(m) length of explosive (m)
Where:CX = Charge end cross-sectionT = Beam thickness when attacked from the side, i.e. depth of beam (m)C = Total charge quantity (blocks)LC = Length of cut (m)
6-2-41. In calculating the charges required for reinforced concrete slabs andbeams, the following general rule applies:
a. Determine CX using the formula given and round up to the nearestquarter block.
b. CX is then multiplied by the length of cut required (LC divided by thelength of the block of explosive, and the answer is rounded up to thenearest quarter block to give the total charge required.
c. The value of CX shall never be less than 1.
d. For T-beams, i.e. composite beam and slab construction, the beams arecut using the formula in paragraph 40. b, while the slabs between thebeams are cut using the formula in para 6-2- 40.a. This procedureapplies only for T-beams in which neither the thickness (depth) of theslab nor the thickness (width ) of the beam exceeds 22.5 cm.
6-2-42. Example. Calculate the charge required to cut a reinforced concretebeam measuring 32 cm thick/deep and 12 cm wide, using C4.
a. CX = 6.4 T2 x length of explosive weight of explosive
CX = 6.4 x .122 x 28 cm 0.56 kg
CX = 4.61, rounded up to 4.75 blocks of C4.
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b. C = CX x ___LC___ length of block
C = 4.75 x 32 cm 28 cm
C =5.43, rounded up to 5.5 blocks of C4
Note, that because of charge placement for beams, the 12 cm width becomes thethickness to be cut, and the 32 cm thickness becomes the continuous length of cut(LC).
6-2-43. Limitations. The only limitation which applies to cutting reinforcedconcrete slabs and beams is that target depth/thickness must not exceed 22.5 cm.
6-2-44. Charge Placement. The following rules apply:
a. When cutting reinforced concrete slabs, the charge must be continuousover the full width of the slab.
b. When cutting reinforced concrete beams, the charge is placed on theside of the beam, and must be continuous over the full depth of thebeam.
6-2-45. Tabular Answers. For tabular answers, see Annex F.
CONCRETE STRIPPING CHARGES
6-2-46. General. The difficulty of attacking large reinforced concrete beamsand slabs is to cut the steel reinforcing bars buried in the concrete. Shaped chargesare limited in their ability to cut through reinforced concrete. The best that can beachieved is to strip the concrete away from the reinforcing bars, attacking thetarget from the top. When a top attack is recommended, all concrete within theindicated wedge-shaped section must be removed, but it is not necessary to cut thesteel reinforcing rods. Such an attack so weakens the structure (specifically, asimply supported span) that it will collapse under its own weight. Concretestripping charges are bulk, surface-placed charges designed to remove concretefrom reinforced concrete beams and slabs to reveal all the steel reinforcement.Although some damage will be caused to the main steel reinforcement, it is not
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possible to predict theextent of the damage.The effect of a concretestripping charge, asillustrated here, pro-viding it is calculatedfor the correct depth oftarget, is: Fig 6-2-10. Effect of a concrete stripping charge
a. To remove all concrete down to the main reinforcement,
b. To remove all concrete below the main reinforcement by spalling.
c. To destroy minor reinforcement near the surface on which the charge isplaced.
d. To damage the main reinforcement to some extent.
6-2-47. Reinforced concrete - large beams and slabs: Reinforced concretebridges can come in various configurations and sizes from concrete slab toconcrete T-beams. A charge must be calculated for each individual component,i.e. for T-beam construction, each beam of a different size and each slab of adifferent size must be calculated separately, using the formula for CW and then C.Once the C for each beam and slab section is known, the total charge quantity canbe determined.
CW = 1.5 x (3.3 T + 0.5)3
C = _____CW x W______ weight of explosive (kg)
WD = 2T + 0.3
Where :CW = the size of charge per metre across the bridge (kg/m)T = the overall depth of beam (includ- ing roadway depth) or slab (m). The minimum value is 0.3 m.C = the total charge required to cut a beam or section of slab (kg)W = the width of the beam or section of slab to be cut (m)WD = ditch width
a. Find the T for the beam and slab.
b. Determine Cw for the beams and slab by using the formula.
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c. Determine the WD by using the formula given and comparing it to theLC (see Chapter 5, Section 3). Decide if charge has to be increased ordecreased IAW the direction at para 6-2-47.g.
d. Determine the charge quantity in kg required for each construction bymultiplying the number of units (beams or slab sections) by its C (i. e.,5 (five beams) x C).
e. Determine the total amount of charge (kg) required by adding all chargequantities together, taking into account the effects of WD and tamping(see para 50. b), add or decrease where necessary.
f. Determine the total quantity of explosive required in unit of issue bydividing the total charge quantity in kg by the weight of explosive (i.e.a block of C4 is 0.56 kg).
g. Ditch Width. A ditch of known width (WD) will be created across thewidth of the bridge by the line of charge. In order to cause a simplysupported bridge to collapse without jamming, the length of section ofthe bridge to be removed (LC), which permits the reinforced concretebridge to collapse, must be compared to the ditch width (WD):
(1) If LC ( Chapter 5 ) is in the order of twice WD, it will be necessaryto place two rows of charges, each of the full mass calculatedabove.
(2) If LC is greater than WD, the charge shall be increased by 10%.
(3) If LC is less than WD, the mass of charge calculated above mustnot be reduced.
6-2-48. Example. For the simply supported RC beam and slab span shown inFig 6-2-11, calculate the stripping charge required to demolish the target, usingC4. given that LC = 1.0 m.
a. For each beam (T = 1.2 m, Width = 0.35 m)CW = 1.5 x (3.3 T + 0.5)3
= 1.5 x (3.3(1.2) + 0.5)3
= 133.07 kg/m runC = 133.07 x 0.35 ) 0.56 = 83.17,rounded up to 83.25 blocks of C4
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Fig 6-2-11. Section of bridge at midspan showing placement ofconcrete stripping charges.
b. For each slab ( T = 0.3 m, Width = 0.9 m)CW = 1.5 x (3.3 T + 0.5)3
CW = 1.5 x (3.3(0.3) + 0.5)3 = 4.96 kg/m runC = 4.96 x 0.9 ? 0.56
= 7.96, rounded up to 8 blocks of C4
c. Determine ditch width (T = 1.2 m)WD = 2 T + 0.3WD = 2 x 1.2 + 0.3WD = 2.4 + 0.3WD = 2.7 m, therefore WD is greater than LC (1.0 m) and only one lineof charge is required
d. Total charge required for 5 beams and 5 slabs = (5 x 83.25) + (5 x 8) = 456.25 blocks of C4
6-2-49. Reinforced concrete - arches:
a. Where the concrete arch is part of a bridge to be demolished, and acomplete cut across the roadway is needed, then a concrete strippingcharge, calculated as per the formulas at para 6-2-47.a , shall be used onthe arch ring and placed as for unreinforced concrete (see para 6-2-37.c).
c. Where the concrete arch is part of a structure such as a multiple archdam, where the requirement is to punch a hole in the arch,
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222 B-GL-361-008/FP-003
and the charge will be well tamped by the water, the size of chargerequired is calculated using the following formula:
C = 32 x Tr Where: C = weight of charge (kg), and Tr = thickness of arch ring at the point of attack (m3)
6-2-50. Limitations. Concrete stripping charges are only recommended fortargets less than 2 m deep. Prestressed concrete is not susceptible to majordamage from stripping charges.
6-2-51. Charge Placement. Concrete stripping charges are placed as follows:
a. Charges must be placed in a continuous line across the full width of thebridge at the point of attack. The shape of the end cross-section of thecharge shall be such that the width is between one and three times theheight.
b. No tamping is required for concrete stripping charges. However, bytamping with two sandbags per kg of explosive, the charge may bereduced by one-third (1/3). The width of ditch formed remains thesame as for the original charge.
c. The ditch width (WD) must be checked against Lc for the particularbridge construction, and the charge increased if necessary.
6-2-52. Tabular Answers. For tabular answers, see Annex G of this chapter.
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B-GL-361-008/FP-003 223
SECTION 3
BREACHING CHARGES
USE
6-3-1. Breaching charges are used mainly to destroy masonry, concrete andreinforced concrete (RC) slab bridges, bridge beams, piers, abutments, and fieldfortifications. The size, shape, placement, and tamping are critical factors.
6-3-2. The size of charge and charge placement are critical because of thestrength and bulk of the material to be demolished. High explosive chargesdetonated in or against a target must produce and transmit enough energy to thetarget to crater or spall the material. The metal reinforcing bars (rebar), inreinforced concrete are not necessarily cut. If it is necessary to remove or cut thereinforcement, the applicable steel cutting charge formula is required to calculatethe second stage of the attack.
CONCRETE BREACHING CHARGE.
6-3-4. General Breaching charges make use of the shattering effect of highexplosives. They provide a rough and ready method of destroying reinforcedconcrete piers and obstacles, such as dragon's teeth, cubes, and walls, but are veryexpensive in explosives. Breaching charges are suitable for attacking RC piles,trestles, and RC piers (up to 1 m thick), as an alternative to the use of shapedcharges.
6-3-5. Charge Calculations. Breaching charges are calculated in accordancewith the table at Fig 6-3-1.
a. Determine the kg/m3 by the type of target in table at Fig 6-3-1 andmultiply by the cubic meters of the target to be destroyed to get thecharge quantity in kg.
b. Divide the charge quantity by the weight of explosive to be used, to getthe total charge quantity in units of issue, i.e. blocks of C4.
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Ser Target Weight (kg) ofexplosive per m3
of material to beremoved
Remarks
(a) (b) (c) (d)1 RC obstacles, e.g.
blocks, dragon's teeth,and cubes
16 If reinforcement isheavy, double charge
2 Masonry walls with noreinforcement
16 Length of wallattacked shall not beless than height
3 RC walls withreinforcement notdenser than 23 cmspacing
32 As for Serial 2
4 RC piers, and wallswith reinforcementdenser than 23 cmspacing
64 As per Serial 2
Fig 6-3-1. Breaching charges for reinforced concrete obstacles and walls.6. Examples
a. Small Obstacle (dragon's tooth) Calculate the charge required todemolish a dragon's tooth (tetrahedron) whose base is 1 m wide, and 1m thick and whose height is 1 m. Solution:
(1) V (Volume of tetrahedron) = base area x height 3
V = (1 m x 1 m) x 1 m 3
V = 0.33 m3
(2) C (weight of explosive to breach concrete target)= 16 kg/m3 VC = 16 kg/m3 x 0.33 m3
C = 5.28 kg of C4, 5.28 =0.56
C =. 9.43, rounded to 9.5 blocks of C4
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B-GL-361-008/FP-003 225
b. Wall. Calculate the charge required to breach a wall ( withreinforcement bars at 20 cm spacing ) that is 2 m high and .3 m thick,so as to provide a gap 4.5 m wide.
(1) V (Volume of concrete to be removed) = W x H x TV = 4.5 m x 2 m x .3 mV = 2.7 m3
(2) C (weight of explosive to breach the wall) = 64 VC = 64 kg/m3 x 2.7 m3
C = 172.8 kg of C4, 172.8 = 308.57, 0.56rounded to 308.75 blocks of C4
c. Reinforced Concrete Pier. Calculate the charge required to breach areinforced concrete pier (unknown reinforcement, so treat as ifheavily/densely reinforced) that is 1 m thick, and 5 m wide.
(1) In calculating the volume of concrete to be removed the widthtaken must be the full width of the pier, and the height must be atleast equal to the pier thickness. Therefore:V (Volume of concrete to be removed) = W x H x TV = 5 m x 1 m x 1 mV = 5 m3
(2) C (weight of explosive to breach the wall) = 64 VC = 64 kg/m3 x 5 m3
C = 320 kg of C4, 320 = 571.42, 0.56rounded to 571.5 blocks of C4
6-3-7. Charge Limitations. For concrete piers over approximately 1 m thick,breaching charges become very expensive in explosives, and borehole chargesshall normally be used instead. Also, in calculating the volume of concrete to beremoved the width taken must be the full width of the pier, and the height must beat least equal to pier thickness.
6-3-8. Charge Placement. Breaching charges shall be placed so that there isa free reflection surface (surface exposed to open air) on the opposite side of thetarget. This free reflection surface is necessary for spalling to occur.
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226 B-GL-361-008/FP-003
a. Small Obstacles (dragon's teeth, cubes, etc)
(1) The charge is spreadso as to keep theratio of width tothickness at about4:1; but thethickness shall notexceed the thicknessof one full box ofexplosive.
(2) The centre of thecharge shall be at
about one-third the height of the obstacle.
Fig 6-3-3 Dragon's teeth prepared for destruction
b. Walls (including reinforced concrete):
(1) The charge calculated in the table at Fig 6-3-1 is placed on theface of the wall to cover the area of the breach required.
(2) The bottom edge of the charge must be at least 30 cm above theground level.
(3) For bestresults, three-quarters of thecharge shallbe placed tooutline thearea of thebreachrequired(ABCD in Fig6-3-4) and theremain-dershall beplaced in thecentre (E).
Fig 6-3-4 Breaching walls.
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B-GL-361-008/FP-003 227
(4) The charge shall be spread so as to to keep the ratio of width tothickness at about 4:1; but the thickness shall not exceed thethickness of one full box of C4 or equivalent explosive. Whenexceptionally large charges are used, this maximum may beexceeded in order to get enough explosives in the right place.
c. Reinforced Concrete (RC)Piers:
(1) The charge shall be continuous across the full width of the pier asshown in Fig 6-3-3, with the centre of the charge at a height aboveground level at least equal to the pier thickness. The onlyexception to this is where the pier is standing in water, in whichcase the charge may be placed just above water level, for ease offixing, but preferably as deep as possible below the surface.
(2) Explosives are normally kept in their boxes for ease of fixing tothe target; the maximum thickness of charge is one wooden box ofC4 or equivalent.
Fig 6-3-5 Breaching reinforced concrete piers.
6-3-9. Tabular Answers. For tabular answers, see Annex H of this chapter.
EAR-MUFF CHARGES
6-3-10. Ear-muff charges, once known as counterforce charges are a specialbreaching technique effective against rectangular shaped masonry or unreinforcedconcrete columns less than 1.2 m thick. The obstacle must have at least three freefaces or be freestanding. If plastic explosives (C4) is used, and properly placedand detonated, ear-muff charges produce excellent results with a relatively small
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amount of explosive. Effectiveness results from the simultaneous detonation oftwo charges placed directly opposite each other and as near the centre of the targetas possible. The size of charge is 2.24 kg (4 blocks of C4) per metre of targetthickness. The total charge is divided in half for each side of the target.
Fig 6-3-4 Ear-muff charge
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B-GL-361-008/FP-003 229
SECTION 4
PIER FOOTING CHARGES
6-4-1. General. Pier footing charges are used to demolish masonry andunreinforced concrete piers. The method makes use of both the shattering andlifting effects of high explosives, but when compared to borehole charges requiresmuch more explosive. However, a pier footing charge is much quicker to prepareand emplace.
6-4-2. Calculations. Charges for demolishing masonry and unreinforcedconcrete piers are calculated using the following formulas:
a. Piers less than 1.8 m thick:
C = ______15 T_______ Weight of Explosive
N = W T
Where:C = Quantity of individual charges of C4 (blocks) T = Pier thickness(m) N = Number of individual charges requiredW = Pier width (m)
(1) Determine the weight of individual charges (C) based on pierthickness. This weight is converted to blocks of C4 by dividingthe total weight by 0.56 kg (the weight of a block of C4) andround up to the nearest quarter block.
(2) Determine the number of individual charges required (N) todemolish the pier by dividing the pier width (W) by pier thickness(T), rounded off to the next highest whole number.
(3) Determine the total quantity of C4 explosive required to demolishthe pier by multiplying the individual charges (C) by the numberof charges required (N).
b. Piers 1.8 m to 2.7 m thick:
C = ______30 T_______ Weight of Explosive
N = W T
Where: C = Quantity of individual charges of C4 (blocks) T = Pier thickness(m) N = Number of individual charges requiredW= Pier width (m)
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230 B-GL-361-008/FP-003
(1) Determine the weight of individual charges (C) of C4 based onpier thickness. This weight is converted to blocks of C4 bydividing the total weight by 0.56 kg (the weight of a block of C4).
(2) Determine the number of individual charges required (N) todemolish the pier by dividing the pier width (W) by pier thickness(T), rounded off to the next highest whole number.
(3) Determine the total quantity of C4 explosive required to demolishthe pier by multiplying the individual charges (C) by the numberof charges required (N).
6-4-3. ExampleCalculate the chargerequired, in blocks ofC4, required todemolish themasonry pier shownat the right, where T= 1.8 m and W = 5m.
Fig 6-4-1 Example masonry pier
a. For a pier 1.8 m thick:C = ____30 T____ weight of explosiveC = 30 kg x 1.8 m ) 0.56 mC = 96.42 rounded up to 96.5 blocks of C4
b. N = W T
N = 5 m/1.8 m
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B-GL-361-008/FP-003 231
N = 2.8, say 3.
c. Total explosive required = C x N= 96.5 x 3= 289.5 blocks of C4
d. Spacing is as shown in Fig 6-4-1.
6-4-4. Limitations. Pier footing charges are employed with the followinglimitations:
a. Pier footing charges are only used against masonry and unreinforcedconcrete piers up to 2.7 m thick.
b. The required amount of charge is much greater than that required forborehole charges. Similarly, by employing full cases vice breakingdown cases, the amount of charge used is much greater.
c. Charges must be in close contact with the pier and well tamped.
6-4-5. Charge Placement. There are three methods of placing the chargesdepending upon the location of the pier to be attacked:
a. When the pier is on a slope. Charges shall be placed in contactwith the pier on the uphillside, either at ground level orburied just below groundlevel. The latter assists in thetamping of the charge. Thecharge shall be well tampedand the difference in heightbetween the bottom of thecharge and the ground levelon the other side of the piermust be not less than 0.45 m.
Fig 6-4-2 Charge placement for pier on slope.
b. When the pier is on level ground. The charges shall be placed on theground surface on one side of the pier. They shall be in close contactwith the pier and well tamped, i.e. one filled sandbag per 0.5 kg ofexplosive. As an alternative to the use of sandbags an equivalentthickness of earth may be placed directly over the charges. This
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232 B-GL-361-008/FP-003
expedient shall be used only when time is short, and special care mustbe taken to protect the firing circuit
and charges fromdisturbance.Although theground is level, thedifference in levelof 0.45 m betweenthe base of thecharge and theground level,discussed in sub-paragraph a, mustbe maintained.Either the chargemust be lifted andsupported up thisdistance (see Fig 6-4-3), or the groundon the other sidemust be excavated
Fig 6-4-3. Charge placement for pier on level ground
c. When the pier footing is standing in water. When a pier is standingin water, charges shall be placed under water, but they shall be in closecontact with the pier. The depth at which the charges are placed mustbe equal to, or greater than, the pier thickness (T) measured from thewater surface to the top of the charge (see Fig 6-4-4). If this is notpossible, the charges may be placed at a lesser depth or above thewater, the charges must be
increased pro-portionately tocompensate forthe reducedtamping. Forexample, if thecharges areplaced at a depthequal to one-halfthe pier
Fig 6-4-4 Charge placement for pier ....................................................
thickness, the charge weight shall be increased by one-half. Similarly, if thecharges are placed at or above the water surface, they must be doubled.
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B-GL-361-008/FP-003 233
6-4-6. As well, pier footing charges must be:
a. Spaced so that the maximum distance between individual charges isequivalent to the thickness of the pier, and with the outer charges beingpositioned at a distance not greater than one-half the thickness of thepier from the edges of the pier. See Figs 6-4-1 and 6-4-2.
b. Placed in close contact with the pier and well tamped. If tamping is notpracticable then the charge must be doubled.
6-4-7. Tabular Answers. For tabular answers, see Annex I of this chapter.
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SECTION 5
BOREHOLE CHARGES
USE
6-5-1. Borehole charges provide an effective and economical method ofdestroying masonry or mass concrete walls, piers, arch rings, timber supports, andtrees. They are not suitable for abutments, where only one face is exposed, as thedetonation tends to produce a series of cones on the open side of the abutmentwithout causing collapse. Borehole charges are also unsuitable for attackinghollow or rubble-filled masonry piers. The reasons for this are that the boreholestend to collapse and cannot be charged; and even if successfully charged, theeffects of the detonation may be dissipated in the loose filling.
6-5-2. Borehole charges may also be used to destroy reinforced concrete (RC)beams and piers. This method is also economical in explosives but expensive intime, as drilling the holes is a slow "trial and error" process owing to the need toavoid the reinforcing rods. In the case of heavy reinforced piers, the mosteffective method of producing boreholes is to use conical shaped charges(Fig 3-2-5).
DRILLING AND CHARGING THE HOLES
6-5-3 In this section, tables which list volumes per hole are based on astandard 5.0 cm diameter drill bit, which tapers off in diameter, depending on thedepth of hole required. The holes are drilled with either a hydraulic or pneumaticair compressor, or the Pionjar. Actual drill bits and diameters can vary dependingon the equipment being used. In some cases, boreholes must be drilled to depthsthat are beyond the capacity of the service equipment. Special drill shaft and bitattachments might be required. Characteristics of current in-service equipmentare as follows:
a. Service compressor and Pionjar concrete drill sizes are as follows:
(1) Shaft lengths are 0.6, 1.2, and 1.8 m, therefore maximum targetthickness attacking one side is 2.7 m, and attacking two sides is3.6 m.
(2) Bit diameters for the compressor range in size from 3.8 cm, 4.4cm and 5.0 cm.
(3) The Pionjar bit diameter size is 2.2 cm.
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B-GL-361-008/FP-003 235
b. For deep boreholes it is advisable to taper the hole in order to preventthe drill from jamming. The recommended depth for each size of bit isas follows:
(1) Up to 1.2 m :- 5.0 cm.
(2) 1.2 - 1.8 m : 4.4 cm.
(3) 1.8 - 2.4 m : 3.8 cm.
6-5-4. To determine the maximum explosive content for uncommoncompressor drill bits, use the following formula:
C = Volume of hole = π x r2 x D Volume of C4 350 cm3
Where: C = charge size (blocks of C4) r = radius of bit (cm) D = depth of hole (cm) π = pi = 3.14
6-5-5. Drilling Times. Approximate times for drilling holes are given inAnnex J to this chapter.
6-5-6. Charging the Boreholes. For horizontal borehole charges, the onlyacceptable service explosives suitable are plastic explosives, i.e. C4. The C4 shallbe unwrapped before placing small quantities of explosive into the hole andtamped with proper tamping rod and using a proper tamping technique. Under nocircumsatnces shll undue force be exerted on thecharge.
CONCRETE AND MASONRY TARGETS
6-5-7. General. Boreholing is achieved by either drilling or by the use ofconical charges. In the case of heavy reinforced targets, the most effectivemethod of producing boreholes is to use shaped charges (see Fig 3-2-5). Whenshaped charges are used, allow 30 minutes for the hole and metal slug to cool off.
6-5-8. Charge Calculation. Charge calculation for creating boreholes arecalculated using the following procedures:
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Ser Material ThicknessNumber ofhorizontal
rows ofholes
Verticalspacingbetween
rows
Depth ofholes
(a) (b) (c) (d) (e) (f)1 Brick or
masonryUp to
1.80 m2 2T
32T3
2 Plain orreinforcedconcrete
Up to1.80 m
3 2T3
2T3
3 Brick, masonry,plain orreinforcedconcrete
1.80 m to2.70 m
3 2T3
2T3
4 Brick, masonry,plain orreinforcedconcrete
2.70 m to3.60 m
3 each side 2T3
T2
5 Brick, masonry,plain orreinforcedconcrete
2.70 m to3.60 m
3 2T3
2T3
6 Brick, masonry,plain or rein-forced concrete
3.60 mto 4.80 m
3 eachside
2T3
T2
Note: When using drill rods up to 1.8 m in length, on targets of thickness2.7 m or less holes can be drilled from one side; however from 2.7 m to3.6 m thick, holes must be drilled from both sides. Similarly using 2.4 mdrill rods targets up to 3.6 m can be drilled from one side, but targets from3.6 m to 4.8 m must be drilled from both sides.Fig 6-5-1. Borehole Charge Placement
a. Determine the number of rows of boreholes required from table at Fig6-5-1.
b. Determine the vertical spacing between rows from Fig 6-5-1.
c. Determine the number of boreholes required. They will normally be atone meter intervals, extending across the full width of the target. Theboreholes at the end of the rows must be at least 0.5 m from the endsand staggered in every alternating row. As seen in Fig 6-5-3.
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B-GL-361-008/FP-003 237
d. Determine the depth of holes required from the table at Fig 6-5-1.
e. Determine the charge quantity per borehole. When starting with a 5.0cm bit as per para 6-5-3.b.of this section, use the table at Fig 6-5-2. Ifusing an uncommon service bits use the calculation at para 6-5-4 of thissection;
(1) In masonry and unreinforced concrete targets the boreholes arehalf filled with explosives. The remainder of the hole isstemmed with damp earth.
(2) For reinforced concrete targets the borehole is completely filledwith explosives.
f. Multiply the charge required per borehole by the total number ofboreholes in order to obtain total charge required.
Note: 1. The blocks of C4 has been rounded up to the nearest quarter. In some instances there may be surplus of explosive when the borehole has been filled.
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C4 Per BoreholeReinforced
concreteMasonry and
unreinforced concreteSer Depth
of hole(m)
Volper hole
(cm3)kg C4 Blks C4 kg C4 Blks C4
(a) (b) (c) (d) (e) (f) (g) 2. Based on volume of explosive and borehole.Fig 6-5-2. Volume of explosive per borehole.
6-5-9. Example. A plain unreinforced concrete pier 2 m thick, 8 m wide and4 m high is to be destroyed. Determine the borehole layout and depth, and theamount of explosive (C4) required:
a. Number of boreholes rows. From table at Fig 6-5-1, Ser 3 (d),three rows required.
b. Vertical spacing of rows. From table at Fig 6-5-1, Ser 3 (e): Vertical spacing = 2T = 2 x 2 m = 1.33 m.
3 3c. Number of boreholes. Holes in alternate rows are staggered, with
centre row being "short", therefore need (2 x 8)+ 7 = 23 holes. (See Fig6-5-3 below.)
Fig 6-5-3 Sketch of borehole layout in concrete (end view at right)
d. Depth of holes. From table at Fig 6-5-1, Ser 3 (f):D = 2T = 2 x 2 = 1.3 m 3 3
e. Amount. of explosive, From table at Fig 6-5-2, Ser 6 (g.), eachborehole requires 4.0 blocks of explosive.
f. Therefore 4 x 23 holes = 92 blocks of C4.
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B-GL-361-008/FP-003 239
6-5-10. Reinforced concrete beams. For beams up to 0.5 m wide, a single 5cm diameter hole is drilled in each beam from the road surface down to therequired two-thirds depth and filled to the top with explosive. For wider beams, 5cm holes shall be drilled at 20 cm centres across the width of the beam. Thiseffect shatters the beams and causes sufficient damage to the deck to ensurecollapse. When drilling, if the drill strikes reinforcing steel near the top of thebeam, there is no alternative but to start again in another place. The advantage ofthis method is that the bridge can remain in use until a few minutes before thecharges are fired. Once the depth of the borehole is known, the amount ofexplosive required is calculated using the table in Fig 6-5-2 of this section.
6-5-11. Limitations. In order to obtain the maximum effect, boreholes in brickor masonry walls shall be drilled at an angle of 30 to 40 degrees to the horizontal,finishing just beyond the centre line of the wall. The charge will then be in thebest position for bursting both faces of the wall. The boreholes shall be as low aspossible so that the flying debris may be more easily smothered, but they must notbe so low that they finish below ground level For example, in brick walls up to0.45 m thick, the spacing shall be between 0.35 m and 0.45 m. In thicker wallsover 0.5 m thick two rows of boreholes are probably advisable to ensure collapse,spaced about 0.6 m apart. In masonry walls, where the material is stronger thanbrick, it is better to reduce the spacing of the boreholes rather than to increase thecharge per hole. For these short holes, tamping is essential.
6-5-12. Charge Placement. The number of borehole charges and theirplacement depends on the size and nature of the target. The following generalrules apply to placing the charges:
a. in arch bridges, boreholes must be below the springing line of the arch,that is, the line along which the lower side of the arch meets the verticalface of the pier.
b. Each row of boreholes must be horizontal and extend across the fullwidth of the target at 1 m centres.
c. When two or more rows of boreholes are required, the holes in adjacentrows must be staggered. This normally results in one row having oneborehole less than the others. Where three rows are necessary the topand bottom rows shall be "long" rows with the "short" row in thecentre.
e. Boreholes at the ends of a row are placed at least 0.5 m from the endsof the target.
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f. The height above ground level of the first row of boreholes will dependupon the need to remove the target completely or to leave anobstruction.
g. When targets are drilled from one side the depth of hole must be twothirds the target thickness.
h. When drilled from both sides, the depth of each hole must be half thetarget thickness. Rows of holes on opposite sides must correspond inlevel, and be staggered horizontally.
TIMBER
6-5-13. General. Plastic explosives are ideal for borehole charges, they may beused to destroy wooden trestles, bridges or timber structures, as well as landclearing. Borehole charges are more economical in explosives than externalcutting charges and are therefor preferred if time permits.
6-5-14. Charge Calculation. For timber targets, the total charge required iscalculated from the following deliberate formulas:
Round Timber.
)100d
2( = C 2
Square/rectangular Timber
)100T
( 2 = C 2
Where:C = charge required (kg)d = the diameter of round timber (cm)T = the thickness of square timber (cm)
a. For targets up to 50 cm diameter, one hole is required.
b. For larger targets, two holes are required where the total calculatedcharge is divided between the two holes.
c. The borehole depth will be two thirds of the target thickness .
6-5-15. Example. Determine borehole layout and explosives required in C4 tofell a tree of 1 m diameter:
a. Two boreholes of depth 0.75 m are required.
b. C = 2 ( d ÷ 100 )2 = = 2 ( 100 cm ÷ 100 )2
= 2 kg of explosives
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B-GL-361-008/FP-003 241
weight of C4 is 0.56 kg, therefore 2 kg ÷ 0.56 cm = 3.57 blocks of C4 rounded to 3.75 blocks.
c. C4 divide d e q ually be tw e e n th e tw o bore h ole s . H ole s at righ tangle s w ith 5.0 cm ve rtical spacing.
6-5-16. Limitations. Borehole charges are not for cutting trees to create anabatis obstacle, because the charge destroys the tree by cutting it off the stump.
6-5-17. Charge Placement. Borehole charhges are placed in timber is asfollows:
a. For rectangular timber, the hole shall be bored into the thickerdimension of the cross-section.
b. The charge is placed in the hole, and the remainder is stemmed withdamp earth.
c. Boreholes are bored at right angles to one another. They must be 5 cmapart vertically (see Figure 6-5-4) and for very large
Fig 6-5-4 Borehole layout in timbertrees, it may be necessary to cut away part of the tree trunk before drilling toachieve the required depth.
6-5-18. Tabular Answers. For tabular answers, see Annex K of this chapter.
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SECTION 6
MINED CHARGES
USE
6-6-1. Mined charges are excavated galleries, shafts, boreholes or othersubterranean receptacles in which explosives are placed to blow up fortifications,roads, bridge piers and bridge abutments, etc. A cratering charge is a chargeplaced [below ground level] at an adequate depth to produce a crater (AAP-6).Thus cratering charges are just a form of mined charges which produce a bowl-shaped cavity. Mined charges are used for cratering/ditching roads and aircraftoperating surfaces, for blowing out retaining walls and bridge abutments, for thedestruction of rubble-filled piers, and for clearing land (to remove stumps andboulders in areas designated for the construction of roads, airfields, landing zonesor buildings). Mined charges may also be used in a row, or rows, to excavate apiece of ground or to form a ditch (i.e., a continuous line of interconnectingcraters). The charges are placed in a variety of ways, and the method selected willdepend upon such factors as time available, size of charge needed, depth at whichthe charge must be placed, soil conditions and equipment available.
CRATERING
6-6-2. General. The tactical objective must be considered when determiningthe size and design of the crater obstacle. As a planning figure, the standard craterobstacle consists of three rows of four craters. The number of craters in each rowmay have to be adjusted based on the reconnaissance details of the specific site.Specifically, they must be designed to effectively deny or disrupt the freedom ofmovement to an opposing force, whether it is moving dismounted, in a wheeledvehicle or tracked vehicle, or in an aircraft. The crater obstacle is enhanced andstrengthened by laying antitank and antipersonnel mines in and around the areawhich causes the opposing force to clear the obstacle of mines before it repairs thecraters themselves. As a minimum, the crater obstacle design shall include thefollowing:
a. a 40 metre gap.
b. be angled 45 degrees across the regular flow of traffic.
c. be strengthened with mines.
d. be covered by direct fire or observed indirect fire.
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B-GL-361-008/FP-003 243
6-6-3. A row of craters across a road, inclined at 45 degrees to the centre lineof the road, presents a greater hazard to tracked vehicles than does a row ofsimilar sized craters formed at right angles to the centre line of the road. This isbecause tracked vehicles tend to slip a track when squaring up to climb out of theobstacle. This method is useful in defiles, on embankments, or other restrictedsites where tracked vehicles must approach the crater along the axis of the roadand cannot change direction to meet the crater at right angles. The 45 degreeinclination may also make it more difficult for bridging to be emplaced or builtacross the gap created.
6-6-4. Calculations. Charges for cratering are calculated using the formulascontained in the following table:
Ser Subgrade Holespacing (s)(m)
Expectedcrater
diameter (m)
Numberof
holes
Minimum chargequantity
(kg)(a) (b) (c) (d) (e) (f)1 Soft
ground2D 3D W
S 9 D3
42 Medium
ground2D 3D W
S 9 D3
23 Hard
groundD 2D W
S 9 D3
2W = the length of desired cut (m) where: D = depth of hole (m)(Camouflet set D=2 m, Auger D=2.4 m)Fig 6-6-1 Calculation table for craters.
a. For placement of charges use the following procedures:
(1) Determine charge depth normally 2 m or 2.4 m and type of ground( see Charge Placement and Table 6-6-1 ).
(2) Determine hole spacing from (c) in table at Fig 6-6-1.
(3) Determine expected crater size from (d) in the table at Fig 6-6-1.
(4) Determine line of cut. For craters across a road at a 45 degreeangle, multiply the width of road by 1.41, ( which is an equal to1/cosine of 45 degrees).
(5) Determine the number holes from (e) table at Fig 6-6-1.
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(6) Determine the number of rows required which in most caseswould be three and multiply that number by the number of holes.
b. For determining charge size carry out the following steps:
(1) Determine charge quantity from (f) in table at Fig 6-6-1.
(2) Multiply the number of holes by charge quantity (if using Trigranround up to the next hole jug i.e. 9 kg).
(3) Multiply 0.5 block of C4 per hole as a priming charge.
6-6-5. Example. Crater a road, using the camouflet method, that is 14 mwide and has soft ground with a subgrade material of sand. Calculate usingTrigran explosive.
a. Charge Placement. From table at Fig 6-6-1 , using soft ground:
(1) Charge depth D = 2 m.
(2) Hole spacing S = 2 x 2 = 4 m.
(3) Expected crater size = 3 x 2 = 6 m.
(4) Line of cut 1.41 x 14 = 19.74 m.
(5) The number of holes = 19.74 ) 4 = 4.93 rounded to 5 holes toensure overlap.
(6) 3 rows of craters 3 x 5 = 15 holes
b. Charge Size:
(1) Charge quantity per hole C = 9 ) 4 x 23 = 18 kg.
(2) 15 holes x 18 kg = 270 kg of Trigran.
(3) 0.5 block of C4 per hole as priming charge = 15 x 0.5 = 7.5blocks.
(4) Total = 270 kg of Trigran and 7.5 blocks of C4.
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B-GL-361-008/FP-003 245
6-6-6. Limitations. The following limitations apply to cratering:
a. Hole depth is the critical limiting factor in cratering charges becausehole depth relates to the amount of space available for the explosivecharge itself and the tamping material. The closer to the surface theexplosive fills the hole, the greater quantity of explosive power that iswasted as it escapes through the top of the hole. The greater the waste,the less the ground is displaced, and consequently, the smaller theresulting crater size. The formula for hard ground accommodates forthis fact by reducing the charge spacing.
b. When cratering "normal" asphalt or concrete paved roads or aircraftoperating surfaces, no increase in explosive quantity is required tocompensate for the presence of the pavement. Although the pavementis usually stronger than the subgrade material, the pavement actuallyhelps to improve the effect of the charge because of confinement.However, special circumstances that have deemed it necessary for thepavement to be especially thick with concrete or asphalt such as withweak subgrade or reinforced aircraft operating surfaces, the explosivequantity would have to be increased to compensate. This will have tobe determined during the reconnaissance.
c In the past, the calculations worked off the premise of "desireddiameter" of the resulting crater without considering the limits orcapabilities of the equipment used. The minimum charge required isdetermined by the depth of the hole and the ground type.
6-6-7. Charge Placement. As previously discussed, there are several factorsthat affect the methods to place cratering charges in the ground. The followingequipment and procedures are used to create chamber and charge holes:
a. camouflet set.
b. earth auger and associated hand/hydraulic tools.
c. power auger on both the APC and SEV MLVW.
d. conical shaped charges.
6-6-8. Depending on the ground type and whether asphalt or concretepavement must be broken first, the number of holes and their spacing could besignificant in time and quantity of explosive required to achieve the desired cratersize.
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6-6-9. A maximum realistic depth of 2 m can be achieved with the camoufletset and 2.4 m with the auger. These depths will achieve a crater diameter of 6 mand 7.2 m respectively. A practical problem exists when breaking throughconcrete or asphalt pavement. The use of conical shaped charges may have to beused first.
6-6-10. When cratering a road, the charges are usually placed in a line at 45degrees to the centre line of the road.
6-6-11. Tabular Answer. For tabular answers, see Annex L of this chapter.
DITCHING
6-6-12. General. Explosives can also be used as an aid to digging ditches, i.e.antitank ditches, fighting and communications trenches. The procedure is to fire asingle row of cratering charges along the centre line of the ditch to be formed (seeFig 6-6-2), leaving any further widening to be effected by firing further chargesalong the lines of the banks of the new channel. The resulting craters mustoverlap so the distance between the charges shall initially be about the same astheir depth, and adjusted later if necessary according to the first results obtained.The charges are normally initiated by a detonating cord ring main.
Fig 6-6-2 Ditching with explosives6-6-13. Charge Calculations and Tabular Answers. The charge will dependupon the depth and width of ditch required, the nature of the ground and thecharge spacing, just as per cratering charge calculations. Therefore, the table atFig 6-6-1 and Annex L may be applied in the determining ditching chargerequirements.
CONTINUOUS MINED CHARGES
6-6-14. General. These charges are placed in a horizontal borehole, usually inthe form of a pipe or culvert, to produce a continuous crater or trench across aroad, aircraft operating surface or embankment, or to blow out the side of a bank.
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6-6-15. Charge Calculations. Continuous mined charges are calculated either:
a. To achieve the diameter (d) of the required crater/ditch, or
b. To break through a least line of resistance, Lr, between the charge andthe ground surface, based on the existing target profile (i.e. using anexisting borehole).
Ser Nature ofsoil
Weight of charge (kg) ofC4 per m run
Remarks
(a) (b) (c) (d)1 Soft ground
(sand, gravel,clay)
4 d2 or 2 Lr2
25 3
2 Mediumground
8 d2 or 4 Lr2
25 33 Hard ground
(rock)16 d2 or 8 Lr
2
25 3
1. d = diameter or widthof crater (m)2. Lr = least line ofresistance (m)3. If the surface is aconcrete slab or heavypavement, increase thecharge by 50%.
Fig 6-6-3. Continuous mined charges - size of charge.
(1) Determine if the weight of charge required is to be based on thediameter (d) of the crater/ditch to be formed, or because the lengthof least resistance (Lr) is defined by an existing culvert, pipe orborehole.
(2) Determine the nature of the soil (soil classification) that must bemoved.
(3) Determine the weight of charge (kg) of C4 explosive, per m run oftarget to be cratered/ditched.
(4) Convert the weight of charge to volume of charge per m run oftarget.
(5) Verify the volume of culvert, pipe or borehole required to housethe charge size determined in sub-paras (1) to (4). Compare this toan existing pipe or culvert, or excavate a borehole of sufficientsize.
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Fig 6-6-4 Example for continuous mined charges and tamping in a culvert
6-6-16. Example. Calculate the continuous mined charge required tocrater/ditch the road, the cross-sectional dimensions of which are given in Fig 6-6-4. Given that the existing culvert is of sufficient size to hold the required chargeand the nature of the soil is compacted gravel surfaced with asphalt.
a. The charge will be placed in an existing culvert at a depth of 2.4 m (Lr= 2.4 m).
b. Weight of charge required= 4 Lr
2
3= 4 x 2.42
3= 7.68 kg per m run
c. If the surface is a concrete slab or heavy pavement, increase the chargeby 50%. Therefore, weight of charge required:= 7.68 kg x 1.5= 11.52 kg/m run
d. To form a continuous ditch, the weight of charge required is:= width of target x charge per m run= 9 m x 11.52 kg/m= 103.68 kg, = 103.68 kg /0.56 kg= 184.25 blocks of C4.
6-6-17. Charge Placement. The charge shall be placed as required by length ofrun (continuous), or divided into charges and placed in accordance with thespacing rules for cratering charges.
6-6-18. The charges are normally placed in existing pipes or culverts runningbeneath a road or runway. If these do not exist, and no other method is possible,
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B-GL-361-008/FP-003 249
pipes or auger holes may be driven parallel to the surface. With long boreholes,the difficulties of controlling the direction of the bore, and of obtaining completedetonation throughout the length, are disadvantages that have to be allowed for.The loading of long holes needs care, particularly in the arrangements forinitiating the charge. One expedient is to bind the detonating cord leads, with athumb knot every 1.5 m, to a bamboo or light wooden pole, mould the explosivearound it, and then insert it in the hole. The depth of the tamping material must beequal or greater than the depth of material above the borehole, or the explosiveforce will escape along the borehole. Otherwise the depth of tamping materialbecomes the least length of resistance.
MASONRY PIERS
6-6-19. General. Mined charges are used to demolish rubble-filled masonrypiers, or solid masonry pier in which demolition chambers have been prepared.
6-6-20. Charge Calculation. The charges required to crater the pier arecalculated in the same manner as cratering in hard ground (rock), see Fig 6-6-1.
6-6-21. Charge Placement. The charges are placed in the prepared chambersand well tamped. In masonry arch bridges, the charges are placed below thespringing line of the arch (as for borehole charges).
MASONRY AND CONCRETE ABUTMENTS AND RETAINING WALLS,MINED CHARGES BEHIND THE TARGET
6-6-22. General. These targets are destroyed by exploding a charge or chargesbehind them. The charges are prepared as a:
a. continuous mined charge;
b. small mined charges; or
c. cratering charges.
6-6-23. Charge Calculations. Whichever type of charge used, two importantmeasurements are needed when designing the charges. They are Lr, the distancefrom the centre of the charge to the outer face of the abutment, and D, the distanceof the charge below ground level, which must be at least 3 Lr/2 (see Fig 6-6-5).
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a. Masonry and Unreinforced Concrete Abutments.
(1) Continuous Mined Charges. The charge is calculated as pertable at Fig 6-6-3, for hard ground (rock). Its effect is to blow outthe wall and produce a crater approximately 2Lr in width.
(2) Small Mined Charges. The charges shall be 2Lr3 (kg) each and
spaced 4/3Lr m apart. The effect is to blow out the wall withoutnecessarily cratering the ground behind it.
(3) Cratering Charges. The charges shall be d3/3 (kg) each, andspaced 2d/3 apart, where d = 2Lr to 3Lr (m).
For all charges, the length Lr is determined during reconnaissance, and thecorresponding depth D and other information is determined from Annex M.
b. Reinforced Concrete Abutments. The charges shall be d3/3 + 10 (kg)each, and spaced 2d/3 m apart, where d = 3Lr (m). The effect of such acratering charge is to collapse the wall by blowing away the concreteand bending the reinforcing bars. The size of charge and chargespacing may also be determined from Annex M. The number ofcharges is given by the width of the abutment divided by the chargespacing, rounded to the nearest whole number.
6-6-24. Example. Determine the charge needed to destroy a reinforcedconcrete abutment 13 m wide and 1.4 m thick using cratering charges. The sitereconnaissance found that the centre of the charge can be placed 0.4 m behind therear face of the wall.
a. Lr = 1.4 m + 0.4 m Lr = 1.8 m
b. d = 3Lrd = 3 x 1.8 md = 5.4 m
c. Weight of Each Charge = d3/3 + 10 (kg)= 5.43/3 + 10= 62.5 kg of Trigran
d. Spacing = 2d/3S = 2 x 5.4 m / 3S = 3.6 m
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e. Number of charges = W/SN = 13 m / 3.6 mN = 3.61, rounded off to nearest whole number = 4
f. Total charge required:
(1) Trigran = N x Weight of each charge (kg)= 4 x 62.5 kg= 250 kg
(2) C4 Priming Charges = N x 1/2 blockC4 = 2 blocks
(3) Total charges = 250 kg Trigran and 2 blocks of C4
6-6-25. Limitations. As per cratering charges. Normally charge placement islimited by the equipment used to excavate boreholes and shafts.
6-6-26. Charge Placement. Charge placement rules are as per crateringcharges and continuous mined charge placement. In all cases, the distance Lr isdetermined during reconnaissance and the depth D at which the charge is placed isequal to 3Lr/2. Fig 6-6-5 and Fig 6-6-6 show charge placement for mined charges.
6-6-27. Tabular Answers. For tabular answers, see Annex M.
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Fig 6-6-5 Mined charges for blowing abutments and retaining walls.
Fig 6-6-6 Charge placement - continuous and small mined charges behind abutments.
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B-GL-361-008/FP-003 253
LAND CLEARANCE, TREE STUMP REMOVAL
6-6-28. General. Tree stumps are generally categorized as being eithertaprooted or laterally rooted. Each type has associated factors that effect the sizeand location of the charge required. Other factors to be considered are the type ofsoil the stump is located in, and whether the tree is green or older (or even dead).For example:
a. Generally oak and pine have taproots, while poplar and spruce normallyhave shallow lateral roots. Trees will however adapt their root systemsto their particular environment.
b. A green stump requires a larger charge than does a dead stump.
c. Stumps are easier to blast out of firm soils than out of loose sandy soils.
6-6-29. Charge Calculation. The simple rule of thumb for calculating treestump charges is 0.5 kg (1 block of C4) of explosive per 0.3 m of diameter fordead stumps and 1. kg (2 blocks of C4) of explosive per 0.3 m of diameter for livestumps. If removing the complete tree, increase the amount of explosive by anadditional 50 percent. If the root system is unknown, assume a lateral rootstructure (see charge placement) and proceed accordingly.
6-6-30. Charge placement. Charge placement rules are based on the rootingsystem on the stumps. There are two types of charge placement and they are asfollows:
a Taprooted Stumps. Two methods are common for removing taprootedstumps. One method (see method (a), Fig 6-6-7), is to drill a hole in thetaproot and place the charge in the hole. Another method (method (b),Fig 6-6-7), is to place charges in contact with the roots on both sides ofthe taproot creating a shearing effect . In both methods, the charges areplaced at a depth approximately equal to the diameter of the stump.
b. Laterally Rooted Stumps. When blasting laterally rooted stumps, drillsloping holes between the roots (method (c),
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and place the charges asclosely to the center ofthe stump as possible, ata depth equal to theradius of the stumpbase. Trees with largelateral roots mayrequire additionalcharges. Place theadditional chargesdirectly underneath thelarge lateral roots.
BOULDER REMOVAL
6-6-31. Blasting is an effectiveway of removing boulders tofacilitate the construction of roads,airfields or buildings. The threemethods used are snakeholing,mudcapping and blockholing. Fig 6-6-7. Charge placement
for stumpblasting
6-6-32. Charge Calculation. Table 6-6-3 lists the charge sizes for the threemethods.
a. Snakeholing. This method involves digging a hole beneath the boulderlarge enough to insert the charge. The charge is packed under andagainst the boulder. ( Fig 6-6-9 (A))
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b. Mudcapping. Used onsurface or slightlyembedded boulders whichhave an exposed seam orcrack that will aid inbreakage. The charge isplace on the boulder witha layer of clay or mudcovering the charge. (Fig6-6-9 (B))
c. Boreholing. This methodsinvolves drilling asufficiently large holeone-third of the way intothe boulder. The hole isfilled with the charge andthen tamped. (Fig 6-6-9(C))
6-6-33. Charge Placement. For charge placement, see Fig 6-6-9.
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SECTION 7
CONCUSSION CHARGES
USE
6-7-1. Concussion charges are bulk explosive charges placed and detonatedinside buildings, making use of pressure build-up produced by the explosion. Inorder for a concussion charge to be effective, all structural weak spots or air gaps,such as windows and doorways, must be blocked.
6-7-2. General. Concussion charges are ineffective where one side of abuilding is much weaker than the others. A strong brick building with a lightcorrugated iron roof, for example, would lose only its roof. Similarly, it is of nouse trying to blow down a framed building by this method, because the walls willbe blown out and the framework may be left standing. The frame must bedemolished by cutting charges, which may first entail stripping off the covering.When the framework is completely concealed within the walls, concussioncharges are first used on the ground floor so the exposed frame can then beattacked.
6-7-3. Charge Calculation. Concussion charge calculation is broken downinto three categories according to target construction:
a. Unreinforced construction such as, corrugated iron, timber, or brick.
b. Light reinforced construction.
c. Reinforced concrete (RC) such as buildings and defences.
6-7-4. Unreinforced Construction. Unreinforced construction is furtherbroken down IAW the wall thickness:
a. For buildings with walls that do not exceed 0.35 m use the followingformula:
C = V 3
Where C = charge size (kg)V = internal volume (m3)
Note: Charges in buildings of two or more stories need only becalculated for the ground floor. If all openings can be blockedefficiently, the charges based on the formula may be halved.b For buildings with walls that exceed 0.35 m thick use the following
formulas:
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C = VT 2
Where C = charge size (kg)V = internal volume (m3)T = thickness of exterior walls in meters
6-6-5. Light Reinforced Construction. For buildings of light reinforcedconstruction use the following formula:
C = VT WhereC = charge size (kg)V = internal volume of ground floor, including interior walls(m3)T = thickness of exterior walls (m), minimum 0.30 m
6-7-6. RC Buildings and Fortifications. For RC buildings and fortificationsuse the following formula:
C = 16KT /VT Where:C = charge size (kg)K = a factor (table Fig 6-7-1) depending on:
(1) the strength of materials used inconstruction;
(2) the shape of the structure; and(3) the number of openings or weak spots
in the walls and roof, through whichthe effect of the charge may bedissipated.
T = wall thickness (m). However, if the roofthickness is greater than the wall thickness andis also greater than one-third the internalheight, then T = roof thickness (m)
V = internal volume of structure (including allinternal walls, floors, etc.) (m3)
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Ser Type of structure Valueof K
(a) (b) (c)1 Brick structures up to 30 m3 internal volume with walls
up to 0.6 m thick (surface or semi-buried)0.1
2 Brick structures of internal volume larger than 30 m3 0.2 –0.4
3 RC air raid shelters (surface or below ground with not more than 1.5 m of cover)
0.4
4 RC tunnels in normal soil (calculate charge for each 30 m run)
1.0
5 RC fortifications with walls up to 0.6 m thick 0.46 RC fortifications with walls over 0.6 m to 1.2 m thick 0.77 RC fortifications with walls over 1.2 m thick 1.1
Fig 6-7-1 Values of K for concussion charges.
6-6-7. Considerations. The following considerations for concussion chargeswill greatly effect charge size if employed:
a. Water concussion charges - Where a building will hold water withoutcollapsing, a charge immersed in the water will destroy the buildingwithout the debris flying. The building shall be filled with water tothree-quarters of its internal height, in which case a charge of one-quarter the size of the calculated charge given by the formula inparagraph 6 is used. If, owing to the danger of excessive flooding, thewater level in the building must be restricted to one-third of the internalheight, the required charge is equal to one-third of the amount given bythe formula. As with normal concussion charges, all openings must beeffectively sealed. Precautions must be taken to ensure that the charge,and firing systems are not displaced or damaged by the water. Theymust be waterproofed as necessary.
b. Explosive tamping charges - In some cases, such as light structures,where the main charges do not exceed 120 kg, the blocking of openingsis achieved by firing tamping charges, placed in the openings, andinitiated simultaneously with the main charges. This method, whichreplaces physical tamping with solid materials, saves time but the effectis only momentary, and a strong blast coming from the opening maycause damage to nearby buildings. Therefore, this means of tampingshall be used on unrestricted sites. Tamping charges are calculatedfrom the formula:
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B-GL-361-008/FP-003 259
CT = 5 x A1 x C A2
Where: CT = weight of tamping charge (kg) A1 = area of opening (m2) A2 = area of roof, external walls (closed in studded walls are used) and floor of building or room (m2) C = weight of main charge (kg).
Note: The tamping charge is suspended in the centre of the opening. For largeopenings, it must be divided into small charges of approximately 5kg andsuspended in a pattern.
6-6-8. Charge Placement. The following charge placement factors apply toconcussion charges:
a. Charges shall normally be broken down into lots of 25 to 100 kg. Lotssmaller than 45 kg shall not be used if the wall thickness exceeds 1.80m.
b. The local shattering effect can also be used to advantage by placing thecharges against strong parts of a building such as supporting columns,chimney breasts and buttresses.
c. The best concussion effect is obtained when the charges are placed nearthe corners of the rooms. If the building has two adjacent rooms of thesame size with walls of the same strength, by placing an excess chargein one room and a reduced charge in the other, in the proportions of 2:1,and detonated simul-taneously, the effects are greatly increased. Thetwo charges together shall equal the total calculated charge for the tworooms.
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ANNEX A
CUTTING CHARGE RECTANGULAR STEEL,CHARGE END CROSS SECTION FOR BLOCKS OF C4
Fig 6C-1 Cutting charge for rectangular timber charge end cross section................................................................................ for blocks of C4
6C-1. Charge Calculation. Charges used for cutting rectangular Timbercan be calculated using the following formula:
C = LC x Cx length of block
WhereC = charge required blocks of C4LC = Length of cut
6C-2. Example. Cut a rectangular piece of Timber 70 cm thick with an LC of95 cm, determine the number of blocks of C4 required:
a. 70 cm thick requires a Cx of 6 blocks of C4 (table).
b. Length of cut is 95 cm divided by 28 cm (C4 length) equals 3.39 blocks.c. 6 x 3.39 = 20.34 blocks say 20.5 blocks of C4.
6C-3. Note: For targets thicker than 0.76 m use borehole charges foreconomical reasons.
NOTE: The blocks of C4 has been rounded up to the nearest quarter. Insome instances there may be surplus of explosive when the borehole hasbeen filled.Fig 6K-1 Borehole charges in timber (C4)
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ANNEX L
CRATERING AND DITCHING CHARGES IN BLOCKS OF C4
Charge depth(m)
Hole spacing(m)
Expectedcrater dia-meter (m)
Chargequantity
(kg)
Target
Camou-flet
Auger Camou-flet
Auger Camou-flet
Auger Camou-flet
Auger
( a ) ( b ) ( c ) ( d ) ( e ) ( f ) ( g ) ( h ) ( j )Softground
2 2.4 4 5 6 7.2 18 32
Mediumground
2 2.4 4 5 6 7.2 36 63
Hardground
2 2.4 2 2.5 4 4.8 36 63
Fig 6L-1 Cratering and ditching charges in blocks of C4
6L-1. Example. Crater a road that is 20 m wide and has soft ground with asubgrade material of sand. Calculate using Trigran with auger.
a. Charge Placement. using soft ground:
(1) Charge depth D = table (c) = 2.4 m.
(2) Hole spacing S = table (e) = 5 m.
(3) Expected crater size = table (g) = 7.2 m.
(4) Line of cut 1.41 x 20 = 28.2 m.
(5) The number of holes = 28.2 ) 5 = 5.64 rounded to 6 holes toensure overlap.
(6) 3 rows of craters 3 x 6 = 18 holes.
b. Charge Size:
(1) Charge quantity per hole C = table (j) = 32 kg.
(2) 16 holes x 32 kg = 512 kg of Trigran.
(3) 0.5 block of C4 per hole as priming charge = 16 x .5 =8 blocks.
(4) Total = 512 kg of Trigran and 8 blocks of C4.
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c. Weight of Each Charge = d3/3 + 10 (kg)= 5.43/3 + 10= 62.5 kg of Trigran
d. Spacing = 2d/3S = 2 x 5.4 m / 3S = 3.6 m
e. Number of charges = W/SN = 13 m / 3.6 mN = 3.61, rounded off to nearest whole number = 4
f. Total charge required:
(1) Trigran = N x Weight of each charge (kg)
= 4 x 62.5 kg
= 250 kg
(2) C4 Priming Charges = N x 1/2 block
C4 = 2 blocks
(3) Total charges = 250 kg Trigran and 2 blocks of C4
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CHAPTER 7CRATERING PROCEDURES AND RELATED SAFETY PRECAUTIONS
GENERAL
7-1. Personnel must be familiar with safety distances outlined in Annexes Aand B to Chapter 4. As with other demolitions, no person shall enter the dangerarea or move from the safe area until the OIC Exercise or site commander hasconfirmed that there were no misfires and the "all clear" signal is given.
7-2. Cratering charges are buried charges, therefore two detonating cordleads long enough to reach from the bottom of the hole, out to the firing circuit arerequired. The detonating cord leads for the chambering charges, when using theCamouflet Set, MK 1, must also be long enough to reach out the camouflet tubeand reach the firing circuit (approximately 12 m of detonating cord). Initiationsets must never be buried.
7-3. The chamber and priming charges will be C4 or similar non-nitroglycerine based explosive (DM 12 or PE 4). Priming charges will normallybe one-half block of C4. The main charge will normally be Trigran, or in someinstances ANFO, and the size will depend on the soil conditions. Calculation ofcharge sizes is covered in Chapter 6
7-4. When stemming the holes, stem at least 0.3 m, or completely to the top.Avoid damage to the detonating cord leads when stemming.
CRATERING WITH AUGERS
7-5. For detailed instructions on the various types of augers in use, refer theapplicable operator manuals. The procedure for augered craters is as follows:
a. drill down 2.4 m using the applicable auger;
b. place half of the main charge into the hole;
c. insert the prepared priming charge down the hole until it rests on themain charge;
d. place the remainder of the main charge down the hole;
e. stem the hole with auger cuttings;
f. connect the detonating cord leads to the initiation set or to the firingcircuit;
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g. ensure all personnel in the danger area are under shelter; and
h. on command of the authorized person, fire the cratering charge.
CRATERING WITH SHAPED CHARGES
7-6. Shaped charges are described in Chapter 3. The procedure for usingshaped charges to create a crater chamber is as follows:
a. place the shaped charge in the desired location;
b. connect it to the initiation set or to the firing circuit;
c. after taking appropriate safety precautions, fire the shaped charges fromthe appropriate safety distance;
d. allow 30 minutes for the holes and metal slugs to cool, or pour water(approximately 10 litres) down the hole and wait 10 minutes;
e. ensure the hole is at the required depth (an auger may be required toclean or finish the hole); and
f. load the main charge with the priming charge, and initiate as describedabove.
CRATERING WITH CAMOUFLET SET MK 1
7-7. The Camouflet Set, MK 1 provides a manual method of creating anunderground chamber for an explosive charge. The components are described inChapter 3. Camouflet chamber charges and priming charges used in thecamouflet procedure must be molded to fit down the tube with little or noresistance. A tamping rod may be used to assist, but excessive force or pressuremust not be used.
7-8. Driving Procedure. The camouflet driving procedure is as follows:
a. if required, break the hard surface using the steel chisel which attachesto the adapter;
b. attach the withdrawal clamp to the tube, slightly below where the heavythumper will reach;
c. place a driving point on one end of the tube and the driving cap on theother end;
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d. slide the thumper over the end with the driving cap, and raise the tubevertical with the point at the desired crater location;
e. using the thumper, drive the tube until the withdrawal clamp is almostto the ground, approximately 1.5 m. Periodically turn the tube with thewithdrawal clamp to ensure the tube does not get stuck; and
f. remove the thumper and driving cap and install the adapter. Continueto drive down until the desired depth is reached (2.4 m can be achievedby digging down slightly before starting to drive the tube).
7-9. Preparing the Chamber. The camouflet chamber is prepared asfollows:
a. normally the tube is removed from the ground using the withdrawalclamp (if there is a danger of the hole collapsing, the tube is lifted outof the ground 0.5 m and secured by lowering the withdrawal clamp tothe ground. If more than one tube requires support, lash pick handles orbranches to the tube using square lashings);
b. if the tube is stuck, use the heavy thumper with the stirrups attached tothe lugs on it and the withdrawal clamp to extract the stuck tube;
c. insert the tamping rod into the hole or down the tube until it touches thebottom and mark it with tape or a pencil to determine the depth of thehole. Remove the tamping rod;
d. insert the prepared chamber charge down the tube and hole to thebottom;
DangerIn the event that explosives become stuck in the camouflet tube and cannotbe removed by slight pressure with the tamping rod, the tube must bedestroyed. If the priming charge is not in place, the tube shall be removedand destroyed by placing a charge on the outside of the tube, adjacent tothe blockage. If the priming charge is already in place, an initiation setshall be attached to the detonating cord leads and the tube destroyed in situ.The safety distance will be the same as for steel cutting.
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e. connect the detonating cord leads to the initiation set or firing circuit;
f. take the appropriate safety precautions, and upon command, initiate thechamber charges from the applicable safety distance;
h. once the "all clear" has been given, insert the tamping rod into the holeand compare the new depth with the mark from the previousmeasurement (this will indicate the size of the chamber); and
j. at this point the decision to use the chamber as is, or to fire anotherchamber charge is made.
7-10. Loading the Chamber.
a. wait 30 minutes for the chamber to cool or pour water down the hole(approximately 10 litres) and wait 10 minutes. Smoke coming fromhole indicates debris may be burning in the chamber and must beextinguished prior to proceeding;
b. place half the main charge in the hole, place the priming charge on topof the first half of the charge and then add the second half of the maincharge;
c. if the camouflet tube has not been fully removed, do so now, beingcareful not to pull on the detonating cord leads as this may pull thepriming charge partially or fully out of the main charge;
d. stem the hole with available material;
e. connect the detonating cord leads to the initiation set or firing circuit;and
f. upon command of the authorized person, fire the charges fromapplicable safety distance.
7-11. Collapsed Chamber. If after measuring the chamber, it is suspected tohave collapsed, one of the following actions will be required:
a. after allowing time for cool down, another chamber charge may beattempted;
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b. a partially collapsed hole may be used as is, which may result in asmaller crater; or
c. the hole is filled in and a new site is selected for the crater.
CRATERING MISFIRES
7-12. In the event of a misfire, the following procedures will apply:
a. all electrically initiated misfires are dealt with after waiting at least 10minutes. For non-electrical misfires, the waiting time is three times theburn time of the length of safety fuze, and not less than 30 minutes.The safety measures in effect for the firing remain in effect for thewaiting period;
b. the minimum number of people will deal with the misfire. Theremainder will evacuate the danger area or remain under cover;
c. if detonating cord leads still protrude from the ground, a new initiationset is attached and the normal firing procedure is followed;
d. if the detonating cord does not protrude from the ground, the stemmingmaterial is removed with a wooden instrument until the detonating cordleads have been found, a new initiation set is then attached, and normalfiring procedures are followed;
e. if the detonating cord cannot be found, the stemming is removed as fardown as possible, and an attempt to initiate the misfired charge , byrepriming the original charge or placing another charge next to it inclose contact;
f. misfired holes containing ANFO must be washed out completely beforea second attempt is made; and
g. a new initiating charge shall be used when initiating a charge in amisfired hole.
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Fig 7-1 Camouflet procedure
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CLEANING CAMOUFLET EQUIPMENT
7-13. The OIC exercise or site commander is responsible for ensuring thecamouflet equipment is cleaned as follows:
a. the tamping rod and the tube will be cleaned with a rag/pull-throughafter each individual use, and if required, washed with soap and wateror windshield washer fluid to remove Trigran dust or C4 residue. Uponcompletion of the task or practice, the camouflet set will be washedbefore storage. Cleaning will take place on the demolition range or tasksite;
b. no metal hardware will be used in any form as part of the cleaning kit;
c. used cleaning material is to be stored in a metal container and returnedto the local ammunition facility for disposal;
d. excess explosives on the inside of the camouflet tube wall shall becarefully scraped off using the tamping rod. The residue and "dirty"cleaning material must be returned to the ammunition facility;
e. tamping rods that cannot be cleaned will be turned in to the ammunitionfacility for destruction; and
f. camouflet tubes that cannot be cleaned (totally blocked) are to bedestroyed as blinds (safety distance as for steel cutting) or turned intothe ammunition facility for destruction.
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CHAPTER 8DEMOLITIONS IN PARTICULAR ENVIRONMENTS
SECTION 1DEMOLITIONS UNDER WATER
SAFETY
8-1-1 The precautions specified in Chapter 2 of B-GL-320-009/FP-001,Engineer Field Manual, Volume 9, Demolitions, Part 1, All Arms, shall be strictlyadhered to during all demolitions training. The underwater environment and thevery nature of diving require additional precautions.
8-1-2. The danger areas for underwater demolitions is the same as for surfacedemolitions (see Section 3, Chapter 2, B-GL-320-09/FP-001, Engineer FieldManual, Volume 9, Demolitions, Part 1, All Arms).
8-1-3. For all underwater demolitions training, a Diving Supervisor will bepresent and will control all aspects of the diving. For underwater demolitionstraining using live explosives, the Diving Supervisor responsibilities remain thesame and will not be combined with those of the OIC Exercise or with those of theRange Safety Officer.
8-1-4. The following precautions will be taken when conducting anydemolitions under water:
a. All divers and swimmers must leave the water before any charges areinitiated.
b. If initiation is from a surface float, the float shall not be secured oranchored over the target, but at a safe distance, so that in the event of amisfire, the OIC firing party will be able to approach the initiation setwithout undue risk from the main charge detonating.
c. When working from a craft with an engine, the motors will be runningbefore the charge is initiated. Paddles or oars shall be available in theboat.
d. The crew of any craft used must be fully briefed as to the action to betaken in the event of an engine failure.
e. The minimum crew in any craft used is two, although more may bespecified.
f. Do not place the safety fuse or detonator under water.
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g. In the event of a misfire, wait 30 minutes, the OIC firing party shallthen remove the means of initiation and where relevant, send a diver toinvestigate
ENVIRONMENTAL (PHYSICAL) EFFECTS
8-1-5. Underwater demolition techniques are much the same as those used ondry land, but water depth, current, tidal conditions, limited visibility and awkwardmanipulation create a very difficult and demanding working environment. Therisk of a mishap, and the possibility of a misfire or of a partial or unsuccessfuldemolition are greater. In addition, water effects the chemical and physicalproperties of the explosive and may restrict the length of time the explosivecharge and accessories may rest in place. Cold water severely reduces themalleability of plastic explosive. Similarly the underwater environment effects thephysical properties of the explosion. Finally, as in all diving tasks, time worksagainst the diver and the planner must consider the total time under compressionin which the work can be completed. Diving procedures are covered in moredetail in B-GL-320-008/FP-001, Engineer Field Manual, Volume 8, CombatDiving.
8-1-6. The underwater environment also affects the target. Waterloggedtimbers are stronger. Concrete and steel become corroded or encrusted making itdifficult to drill, and to secure charges in direct contact with the target.
8-1-7. Overpressure. In air, the impact of the gases released by the explosiondevelops a pressure wave that travels away from the detonated explosive,diminishing as the distance from the point of origin increases, and being quicklydissipated into the atmosphere. Underwater, not only does the impact of thereleased gases on the surrounding envelope of water develop a pressure wave, butthe potential energy of the gas pressure changes to kinetic energy as the water isthrust back. As the gases expand the pressure within the gas bubble drops, tobelow that of the surrounding water, allowing the water in its turn to exertsufficient pressure to collapse the bubble. The potential energy in therecompressed gases then causes the gas to expand again, and this new impactagainst the surrounding water causes a second pressure wave similar to the first.These successive pressure waves are called bubble pulses. Although the peakpressure in a bubble pulse is very much lower than the peak shock pressure at agiven distance from the same charge, a considerable flow of water accompaniesthe bubble oscillation, and velocities as high as 100 m/s may be imparted to thewater. The kinetic energy of this high velocity water is a potential source ofdamage to structures within two or three bubble radii, and this must be consideredwhen planning underwater demolitions. Objects under water may be affected bythe bubble pulses as well as the effect of the water being pushed back bodily bythe expanding gases. Shallow water reduces its effect, while a hard bottom mayserve to reflect and strength the wave.
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8-1-8. The overpressure created by underwater explosives can causesympathetic detonation of mines laid beneath the surface at likely fording andswim sites . Overpressure can cause serious injury or death to divers and be usedas a defence against enemy divers.
DANGEROverpressures of 3500 kPa cause damage to the lungs and intestinal tractand pressures over 14000 kPa can cause death. (B-GL-320-008/FP-001)
8-1-9. Calculation of Overpressure. Only the proximity and size of theexplosive are considered. The pressure exerted at a given distance by anunderwater explosion is expressed by this formula from B-GL-320-008/FP-001:This formula is not to be used to calculate safety distances
P = 3816 C d
where: P = pressure (kPa)C = mass of C4 (kg)
d = distance from charge (m)
8-1-10. Depth. The tamping effect of water during steel cutting is negligible.In rock and concrete blasting, the degree of shattering of the target is usuallyimproved as a result of tamping, and flying debris is reduced. However, in somecases the weight of water above the target (hard rock on the bottom of a channel)also serves to strengthen the material by preventing it from being blown out of thehole, making removal by clamshell or dredging machines necessary.
8-1-11. Charge Size. Charges must be large enough to do the job, but compactenough to be easily handled underwater. Bulk explosives of up to 50 kg can becarried easily, but consideration should be given to lowering prepared chargesfrom the surface, or off-setting their weight with flotation bladders.
8-1-12. Retarding Effect. Water between the charge and the target will greatlyaffect a cutting charge. The charge must be placed and secured in direct contactwith the target. If shaped charges are used, an artificial air gap must be created.The retarding effect of the water can be reduced (for breaching or cutting charges)if a technique termed "bubble delay" is used. In this a bubble of gas produced bya small charge, or detonating cord coiled around but not touching the main charge,is used to remove water from immediately around the target to be destroyed.Detonation of the main charge is delayed a few milliseconds so that it occurs afterthe target has been enveloped by the gas bubble. This is a recommended techniquefor use against small underwater targets at depths from 3 to 30 m. Delaydetonators are not a service accessory but are commonly used in quarrying, andso available commercially.
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8-1-13. Location of Charge. The effects of an underwater explosion are alsogreatly influenced by the position of the charge relative to the water surface, andthe sea or river bed. However, in depths of less than 3.5 m, the tamping effect canbe ignored since near the surface it is negligible. The contour and type of the bedcan also modify the effects of the explosion. It is therefore difficult to predict,with any accuracy, the effect of any charge detonated under water.
RECONNAISSANCE AND PLANNING
8-1-14. Targets. Military divers encounter a wide variety of demolitiontargets. The method of attack depends on the tactical situation and on availableinformation. In a secure area, the destruction of a highway bridge may be a majorproject involving drilling and steel cutting operations above and below thesurface. However, the clearing of mines from a crossing may involve the use ofbasic charges, perhaps while under observation and fire.
8-1-15. When a demolition task requires the employment of divers, a divingreconnaissance is conducted in addition to the surface tactical and technical recce.Information obtained from the diving reconnaissance assists in determining:
a. the method of attack, including: types of charges required, chargeplacement, and the method of securing charges to the target; and
b. diving resources required, including: diving personnel, specializedtools and equipment, and surface support.
The importance of detailed reconnaissance cannot be over stressed. Onceprepared, charges cannot be forced to fit the target underwater as easily as on thesurface.
8-1-16. Sequence. Underwater demolitions follow the same sequence assurface demolitions. Once the reconnaissance and planning have been completed,the following activities occur:
a. the charges and firing systems are prepared on shore;
b. charge fastening devices are prepared and installed on the target bydivers;
c. charges are placed on the target and properly secured;
d. the ring main is laid;
e. unless the operational situation dictates, all divers leave the waterbefore the initiation set is attached to the ring main;
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f. the demolition is fired; and
g. unless the operational situation does not permit it, divers verify thesuccessful detonation of all the charges.
METHOD OF ATTACK
8-1-17. General. Calculations and methods of attack are the same as forsurface demolitions taking into consideration the following factors:
a. Buoyancy. The weight of the target in the water, as opposed to air,serves to give it added stability. Many surface demolition techniquesuse the weight of the target to aid in its destruction. This may not bepossible underwater and a greater amount of explosive may be required.
b. Springing Action. Concrete and timber pilings often spring back fromcutting charges sustaining minimum damage. To compensate for thiseffect, charges may have to be placed on opposite sides of the targetand staggered to achieve a scissors effect.
c. Relief. Surfaces below the mud line meet more resistance than thosesurrounded by water. When obstacles such as bridge piers must beremoved below the mud line, a trench is dug around the base to allowthe pier to expand more easily when the charge is fired.
8-1-18. Cutting
a. Steel. Calculate the charge as described in Chapter 6, Section 2, andthen double the figure obtained. The charges are used in a similarmanner to those on dry land.
b. Timber. Calculate the charge as described in Chapter 6, Section 2, andthen double the figure obtained. However, experience may show that alesser charge can be used.
c. Pile Cutting. To cut a single pile or upright construction, calculate theexplosive required and make up the charge into a necklace at least 1.3times as large as the circumference of the pile. Then, using a light line,lower the charge, complete with detonating cord lead, down over thepile to the point where the cut is required (It may be necessary toexcavate the ground around the foot of the pile.). Keep one side of thenecklace charge higher than the other so that the charge lies at an anglearound the pile. Timber pilings may be cut underwater by placingoff-set earmuff charges on the pile. Cartridges are placed directly onthe pile. Another method is to load a transverse borehole that is drilled
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almost through the piling. This requires less explosive but requires adiver to drill through the pile.
d. Linear Charges. The use of a copper or plastic pipe filled withexplosive, and bent to conform to the shape of the target, can be aneffective method.
8-1-19. Breaching. For concrete and masonry use the amount of explosivecalculated for an above ground untamped breaching charge (see Chapter 6,Section 3). In general, a charge of 32 kg of explosive per cubic metre of concreteto be removed should suffice for a small target of any shape.
8-1-20. Boreholes. Use the same charge as would be required above water (seeChapter 6, Section 5). A template shall be used to ensure that the holes are drilledat their correct spacing, and that they can be relocated with ease. A good templatecan be made of tubular scaffolding. After drilling, the holes must be plugged toprevent back filling. Since the debris is not blown out of the hole, the spacing ofboreholes must be such that removal of debris by dredging is possible.
8-1-21. Excavation. Submarine blasting is required for excavating mostharbours, channels, canals, and other underwater trenches. Hard compacted sand,dense clay, or rock bottom material must be drilled and blasted before excavationwith conventional equipment. Rock blasting techniques are described in B-CE-320-012/FP-004.
8-1-22. Submerged Obstacles. Removing submerged obstacles in channelsand rivers usually follows general underwater demolition practices. Explosivesshall be placed under the centre and immediately against the obstruction wheneverpossible. In removing elongated objects, it is often necessary to place severalcharges at intervals.
8-1-23. Sand Bars.In calm, shallowwater, channels can becleared through sandbars with Bangaloretorpedoes, Twocharges as long as thelength of channeldesired are preparedbefore hand. Joints inalternate lines of tor-pedoes shall be offset.Each charge is primedfrom one end. Thetwo charges are thenplaced parallel acrossthe sand
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Fig 8-1-1 Blasting a channel through a sand barusing Bangalore torpedoes
bar and 3 m apart. When the charges are placed, all detonating cord leads arebrought together at one point and two initiation sets are attached so that either willfire both the lines simultaneously. The resulting blast produces a channel 10 to 12m wide and up to 2 m deeper than the bar. When possible, electric initiation isdesirable and two electric detonators in series, are taped to the four detonatingcord leads. The channel shall be marked immediately afterwards.
8-1-24. Floating Obstacles. These obstacles may be destroyed using hand-placed charges as follows:
a. Booms. Floating booms may be severed by the detonation of smallcharges. In running water it is preferable to sever the boom at one end,allowing the force of the current to swing the boom to the oppositeshore where it will be beached and will not constitute a hazard tobridges or vessels downstream. Midstream anchorages must also besevered. In still water the boom may be severed at one end, and hauledto the opposite shore by a vehicle. Otherwise, they must be severed ina number of places and allowed to drift. Charges shall be placed on theboom logs rather than the hardware. Caution must always be exercisedas the booms may be booby-trapped.
b. Cables. Cables which are suspended a few feet below the surface byflotation elements may be removed in the same manner as booms.
c. Nets. Steel nets in running water may be removed by detonating acharge at one end and allowing the net to fall to the bottom as the freeend is carried downstream. A net may also be severed at one end byattacking it as an underwater obstacle. If necessary, small nets may bebrought to the surface near one end by attaching empty oil drums orsimilar flotation elements. The submerged section of the net is thensevered by charges placed from the surface.
8-1-25. Log Obstacles. Log obstacles may be encountered at likely watercrossing sites or beach landing areas. They are normally constructed using heavylogs or timbers embedded in the ground with ends projecting 0.8 to 1.5 m. Logramps and log cribs are also used. They may be built both above and below thewater's surface. They are normally reinforced with mines and booby-traps. Theobstacles may be removed using hand placed charges.
a. Individual obstacles. Methods of breaching concrete obstacles arealso effective against steel or wood obstacles such as rails, tetrahedrons,hedgehogs, and posts. Plastic explosive is recommended since it caneasily be moulded around steel or wood forms, ensuring good contact.
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Quantities of explosives are computed from standard demolitionformulas. This may be difficult with odd shaped obstacles. Generally,the charge is placed at a joint where the obstacle is weakest. Whenobstacles are driven into the ground, the charge shall be attached to theobstacle as close to the ground as possible.
b. Log cribs. A log crib is demolished by 15 to 20 kg of explosive placedin a hole in the centre of the earth fill and two-thirds the depth of thecrib. It must be thoroughly tamped. Similar charges are placed at 3 mcentres over the length of the crib.
c. Log scaffolding. Against log scaffolding, more frequently found inunderwater obstacles, nine sections of Bangalore torpedo are used toform a charge consisting of three lengths of torpedo. The three lengthsare tied together and placed at right angles to the line of scaffolding.The number of charges used depends upon the width of breach desired.Each charge clears a lane approximately 4 m wide.
8-1-26. Shallow Cratering. Submarine rock can often be broken up using thismethod. It is used at depths of less than about 8 m due to the large shock wavesproduced. A typical pattern would involve 30 kg charges spaced 2 m apart. Thismay also be an effective method of creating trenches in silt and sand.
8-1-27. Ditching. Ditching charge calculations described in Chapter 6, Section6, apply to underwater ditching tasks
8-1-28. Recovery of Targets. If it is necessary to recover or remove part of atarget after the demolition, a recovery line and float shall be attached to it. Inorder to reduce the chances of the recovery line itself being damaged by theexplosion, the first 15 m of the line should be weighted so that it lies below thetarget, and where possible, on the river or sea bed.
PREPARATION OF CHARGES
8-1-29. Preparation of Charges. Service explosives and accessories are quitesuitable. However, for reasons of time, poor visibility and awkward manipulationunderwater, it is important that the maximum amount of preparation of thecharges be done on the surface. Line or rope charges made to measure willfrequently be prepared, and explosives for point charges will be made up toprecise size and in a manner for easy handling. Waterproofing of charges beingused immediately is not critical, but they shall be wrapped with plastic or cloth toensure their integrity once submerged. Demolitions involving any delay shall bewaterproofed to the maximum extent possible.
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8-1-30. Shaped Charges. Shaped charges are less effective when firedunderwater, since water in the stand-off area impedes the formation of the jet.This can be overcome to some extent by reducing the stand-off distance andmaintaining a water-tight air space between the charge and the target, or byinserting or other low density plastic foam such as styrofoam. It may also benecessary to place the charge inside a plastic bag, box or a hose, to prevent thewater current breaking up the charge.
8-1-31. Charge Containers.Shaped demolition charge con-tainers designed for use in ord-nance disposal work may be usedin underwater steel cutting. Thecontainers hold the explosive toform the shaped charge and areavailable in several shapes andsizes. Rectangular shaped linearcontainers have been designedprimarily for underwater use.
Fig 8-1-2 Typical shaped charge container
8-1-32. Sheet Explosive. Sheet explosive is more flexible at low temperaturethan plastic explosive and is more easily cut and moulded to target surfaces. It isavailable in a number of configurations including rolls, sheets, ribbons, and cords.Thickness and diameter range from 3 to 16 mm.
8-1-33. Satchel Charges. Satchel charges can be prepared locally using smallpacks or sand bags. Care must be taken to ensure that such improvised chargesare purged of all trapped air before they are submerged so that their changingbuoyancy does not hinder the carriage and placement of the charge. The Mk 138,Mod 1 satchel charge, described in Chapter 3, has detonating cord designed to bemore pliable for use underwater
8-1-34. Detonating Cord. Detonating cord, with a double thumb knot, isembedded in the charge while the other end is kept at the surface. Special careshall be taken to achieve a good seal where the detonating cord enters the charge,otherwise the current may damage the charge. Also the detonator is doubledcrimped to the safety fuse, for waterproofing purposes. Current detonating cord iswaterproof for up to 24 hours. However, once submerged, water seeps into openends much more quickly than along its girth. For this reason, an overhang of atleast 0.5 m of detonating cord shall be left from the point where it is attached tothe ring main. These leads shall then be coiled and taped to prevent their snaggingwhile being placed. In cases where charges are to be left submerged for relativelylong periods, the ends shall be dipped in melted sealing wax, taped, and dippedagain.
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8-1-35. Safety Fuse. The rate at which safety fuse burns is affected by depthand by water temperature. If underwater initiation using safety fuse is employed,the burning rate underwater shall be determined by trial prior to preparation of theinitiation sets. When performing a demolition task in very cold water, manymisfires may be experienced due to the fracturing of the watertight cover aroundthe fuse. This problem can be partially solved by preparing safety fuse so that itcannot flex once it is exposed to the cold. A good method is to wrap the fusearound a piece of rigid material and tape it firmly in place.
SECURING THE CHARGES
8-1-36. Securing Charges. All fastenings for charges shall be prepared beforethe charges are lowered to the diver. Charges are fastened in the same manner ason the surface, bearing in mind that problems can be caused by current anddrifting debris. Wood bracing also tends to float away from divers and is difficultto position. Charges can be held in place using wire, cord or nylon strapping.Bolt gun fasteners and staple guns may also be of use. Detonating cord leads shallbe attached to the ring main using detonating cord clips or girth hitches asadhesive tape cannot be applied underwater.
FIRING CIRCUIT
8-1-37. Under normal circumstances, a ring main is used underwater to connectmultiple charges for simultaneous detonation. Where practical, given the tacticalsituation and the safety of the divers, maximum firing circuits will de employed.
8-1-38. Ring Main. Consideration of the effects of drift and current are mostimportant in laying out ring mains. As detonating cord becomes brittle in extremecold, care must be taken to ensure there are no kinks or sharp bends. Ring mainsshould be laid from the upstream side of the target, with the diver working on thedownstream side. They should be securely attached to the structure or held to thebottom using weights. When the detonating cord leads from the target to theinitiation point span a distance of over 15 m, and the current is strong enough tocause it to drift considerably, the leads shall be run along a rope or cable designedto carry the load or run along the bottom and firmly anchored in place. Failure tosecure the detonating cord underwater may result in the tide or current moving it,and this may result in cut-offs and failure of the demolition. Detonating cord shallnot be placed in tension.
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Fig 8-1-3 Initiating charges underwater
8-1-39. Detonating Cord Leads. Double detonating cord leads are used toconnect each charge to the ring main. Detonating cord junctions are best securedwith spun yarn, string, or tape (if possible), etc., to avoid the risk of the cord beingpulled out of the detonating cord junction clip by the force of the current.Detonating cord leads must have the usual 50 cm spare end.
INITIATION SETS
8-1-40. Initiation. As suitable underwater initiating devices are not yetavailable, all underwater demolitions shall be fired from above the surface. Dualinitiation is mandatory, however both initiation sets may be connected to the sameinitiation point.
a. Non-electric. A dual non-electric initiation set (Fig 8-1-4) forunderwater is created as follows:
(1) waterproof both the detonators and the M60 Igniters;
(2) cut sufficient safety fuze;
(3) attach the detonators and M60 Igniters to the safety fuze;
(4) cut sufficient detonating cord for the ring main (normally threetimes the depth) and form a cradle in the middle (approximately30 cm long);
(5) tape the detonators, then the safety fuze to the cradle; and
(6) tape the safety fuze to a float just in front of the M60 Igniters.
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Fig 8-1-4 Underwater Dual Non-Electric Initiation Set
b. Electric. A dual electric initiation set (Fig 8-1-4) is created as follows:
(1) test the electric detonators and demolition cable;
(2) tie a thumb knot approximately 10 cm from the running end of thedemolition cable;
(3) cut the detonator leg wires to 60 cm as 3 m is too difficult to workwith, then splice the detonators and demolition cable in series;
(4) waterproof the splices;
(5) test the circuit;
(6) cut sufficient detonating cord to form the ring main and form acradle (30 cm long) in the centre;
(7) tape the detonators to the charge end of the cradle and the knot inthe demolition cable to the top of the cradle;
(8) tape any excess wire ends to the cradle; and
(9) secure to float.
Fig 8-1-5 Underwater dual electric initiation
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Fig 8-1-6 Dual initiation secured to detonating cord
8-1-41. Normally, safety fuze is not placed under water because its rate ofburning increases when the fuse is under pressure, and when the detonator iscrimped to the end the loin is unlikely to be waterproof. Any water betweensafety fuse and detonator is likely to cause a misfire. However, if it is essentialthat the fuse be ignited under water , the length of fuse shall be tested for rate ofburning underwater to permit the divers or swimmers to leave the water beforethe charges detonate (see Section 3, Chapter 2, B-GL-320-09/FP-001, EngineerField Manual, Volume 9, Demolitions, Part 1, All Arms)
8-1-42. In many instances the detonating cord will be quite long, and may beaffected by current or tidal flow, in that it is liable to damage from nicks andrubbing against rocks, etc. If necessary, the detonating cord shall be secured atintervals to a light line which has one end securely fixed to the target area (See Fig8-1-3).
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SECTION 2DEMOLITIONS IN SUB - FREEZING CONDITIONS
EFFECTS OF COLD
8-2-1. All military explosives and accessories are suitable for use in extremecold climates. Detonating cord and safety fuze have a tendency to become brittleand crack. Care should be taken that these items are not repeatedly bent andstraightened. The use of electric detonators may alleviate the problem.
8-2-2. Military plastic explosives and accessories remain effective intemperatures to -55°C, however, it is advisable to keep them warm if at allpossible. Small quantities may be carried by personnel inside parkas, etc. Thecutting effect of plastic explosives is reduced slightly when cold. Wheneverpossible, charges and detonating cord should be prepared in a heated tent orbuilding.
DEMOLITIONS IN PERMAFROST
8-2-3. The use of explosives in permafrost is usually necessary because of thereduced effectiveness of engineer heavy equipment or in a situation whereobstacles are required to deny an area to the opposing force. Permafrost usuallyremains in large chunks when broken up by explosives. For this reason, largerthan normal charges should be used to lift these chunks. Charge size is explainedin Chapter 6, Section 6. All charges in permafrost are to be calculated as for hardground. It is recommended to use explosives with a lower velocity of detonationbecause it normally produces better results.
ICE DEMOLITIONS
8-2-4. Natural ice covers are used extensively as winter transportation routesand construction platforms in cold regions. For military purposes it is thereforedesirable to be able to deny the use of these as transportation routes should theneed arise.
8-2-5. Another consideration in the preparation of ice demolitions is the lengthof time the explosives will be exposed to water before firing. Careful selection ofexplosives is critical because some types of explosives have little or no resistanceto water. The duration of the obstacle created is also of importance. After aportion of the ice sheet is destroyed, it will start to "heal" itself by freezing at arate governed by the weather conditions.
8-2-6. Charges placed under the ice will produce the best effects, however iftime is limited surface laid charges or manufactured charges may be used.
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SUB-SURFACE CHARGES
8-2-7. Sub-surface charges are the preferred method of ice demolition if timeis not a consideration. The most effective charges are placed under the ice atcalculated depth. They can be used individually as point targets or as a group tocreate linear openings. Sub-surface charges can be placed through access holeswith the use of poles or divers.
8-2-8. Calculate charge size using the following formula:
C = 4.48 Ti3 where C = charge C4 (kg)
Ti = thickness of ice (m)
8-2-9. Determine suspension depth using the following formula:
D = 0.84 Ti where Ti = thickness of ice (m)D = depth of charge below bottom of ice (m)
8-2-10. Determine Expected Diameter of crater using the following formula:
d = 9.8 Ti where d = expected crater diameter (m)Ti = thickness of ice (m)
8-2-11. Spacing. When using multiple charges for linear obstacles chargespacing equals diameter.
8-2-12. Example. Calculate the charge size, charge depth below the ice andthe linear spacing for ice with a thickness of 0.35 m.
a. Calculate charge size.C = 4.48 Ti
3 = 4.48 x(0.353) = 0.19 kg C4
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Convert to blocks C4 0.19 ÷ 0.56 = 0.34, rounded up to 0.5 blocksC4
b. Calculate charge depth below the ice bottom.D = 0.84 Ti = 0.84 x 0.35 = 0.29 (from bottom of ice)
c. Calculate the expected crater diameter.D = (9.8 Ti) = (9.8 x 0.35) = 3.4
d. Charge spacing.Spacing = diameter = 3.4 m
8-2-13. Hasty Charge Calculation. The table in Fig 8-2-2 is a hasty methodof determining charge size and placement. Once the ice thickness is measured,round up to the next highest number and use the applicable information. Forthicker ice use the formula.
8-2-13. In situations where the calculated depth (D) is greater than the water isdeep, for example as you approach shore, the charge is centred between theunderside of the ice and the bottom.
SURFACE CHARGES
8-2-15. There is no definitive method for calculating charge sizes for surfacecharges. The method discussed in this section has not been extensively tried and atest shot should be conducted. The following formula is based on Fonstad's IceDemolitions of Ice Sheets, converted to give the charge as kg C4. Fig 8-2-2 isbased on this formula and is a quick guide.
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d = (1.5 C) where C = C4 charge size (kg)d = expected crater diameter (m)
8-2-16. Tamping. Tamping will increase the effectiveness of surface charges.Tamping material should be substantial enough to provide good confinement ofthe charge (sandbags, bulk sand or earth).
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CHAPTER 9BATTLE SIMULATION
GENERAL
9-1. Simulation can be incorporated into fire power demonstrations orduring training exercises to project realistic combat conditions while minimizingrisk of injury to personnel and preventing unacceptable damage. Realistic battlenoise, flash, effect, smoke, and rates of fire can be simulated with the use ofexplosives, accessories or training munitions. The information and recommendedmethods presented in this section provide an aide to facilitate battle simulationoperations and may be modified to meet specific conditions.
SAFETY PRECAUTIONS
9-2. Battle simulation requires additional special safety procedures. Thelikelihood of personnel, vehicles, equipment and possibly aircraft being in ormoving in close proximity to demolitions requires strict adherence to size,quantity and type of explosives, munitions and accessories which are used.Applicable safety distances must be established and enforced. Fences, sentries,pickets, mine tape and coloured lights may be required to control or preventaccidental passage through simulation areas. Detailed briefings shall beconducted for all personnel to ensure complete understanding of all aspects of theoperation. Coordination and control is of the utmost importance.
9-3. RF Hazards. Electrical demolition cable, detonators and igniter leadsare all capable of absorbing and conducting electrical energy transmitted orproduced by remote sources, such as radio transmitters, radars, or electricalmachinery. To reduce the possibility of accidental initiation, the electricalprocedures prescribed in Chapter 4 shall be strictly adhered to.
9-4. When using explosives for simulation, a number of safety precautionsshall be followed:
a. because personnel and vehicles may be required to move through ornear areas where simulation explosives have been placed, positivecontrol is required at all times, therefore only electric initiation may beused;
b. charges will not be buried; they will be placed on the ground so as notto cause flying debris;
c. when there is a possibility of two charges detonating almostsimultaneously, the safety distance to be observed is to be assessed asthough one charge, equal to the sum of both charges;
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d. where movement is involved (for example: an assault on a defensiveposition) charges are not to exceed 0.5 kg;
e. where visual control is not possible, the charges are to be enclosed by amarked fence. Charges fired at night are to be enclosed in a whitetaped fence, 100 m minimum from the charge;
f. where vehicles are required to move in the training area at night, atleast two sentries with warning lights are to be posted at each battlesimulation area;
g. all troops in the area are to be warned of the location and nature ofbattle simulation arrangements, and instructed to watch for warninglights and fences;
h. to avoid errors in judgement by the firer, the limits of all danger areasshall be marked so as to be visible to the firer. Small pickets, carefullyplaced, shall guide the firer without necessarily disclosing the chargelocation to the personnel being trained;
j. no power source will be brought within 5 m of the firing leads and nocharges fired until all personnel are under cover or at least at the correctsafety distance from the placed charges;
k. electric leads shall not be jerked once the detonators are in place. Allelectrical connections will be well secured to ensure that vibrationsfrom the first charges fired do not cause misfires in successive charges;and
m. the danger to helicopters and aircraft flying at low level shall be takeninto consideration. All pilots will be warned of the location and natureof battle simulation.
SAFETY DISTANCES
9-5. The safety distances in Fig 9-1 are the minimum safety distances forspecific explosives, accessories and training munitions which may be used inbattle simulations. If other items are to be used, the correct safety distance mustbe researched. Vertical safety distances are the same as the horizontal distances.
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Ser Battle Simulations Safety Distance(a) (b) (c)1 Detonators and detonating cord in the
9-6. Battle simulations usually employ more electrical accessories thanother tasks. Consequently, the electrical requirements are greater and it becomesnecessary to calculate resistance and conduct checks to reduce the likelihood ofmisfires. Normal power sources are the Battlefield Effects Remote Firing System(BERFS) and the ZEB blasting machine.
9-7. Battlefield Effects Remote Firing System (BERFS). BERFS is usedto initiate effective battle noise simulation during field training and exercises forground forces. It is the primary method of conducting battlefield simulation.BERFS operates by using UHF radio link from the firing point to the explosive(Fig 9-2), overcoming the disadvantages associated with cable based systems.The BERFS is guaranteed to function with up to 25 ohms resistance. Eachreceiver is capable of firing 10 circuits simulations. The mini-mum distancebetween charges, and between the charge and receiver is 10 m. The minimumdistance between simulations is 10 m.
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Fig 9-2 BERFS layout
9-8. ZEB Blasting Machine. The ZEB blasting machine is specificallydesigned to generate electrical current for electrical demolitions and consequentlyit is one of the best power sources available. It operates on circuits with amaximum resistance of 260 ohms.
9-9. Other Methods. Other frequently used power sources such asbatteries, vehicles, and generators, etc, have varying capabilities. Prior toplanning to use one of these power sources, calculate its output to ensure that itcan meet the requirements. Complete calculations for any circuit involves thedetermination of the current (amperes), the voltage (volts) and the power (watts)needed to fire the circuit. Computation of the voltage and of the power includesthe determination of the system resistance (ohms) which can be done with theprocedure described in Chapter 4.
CONTROL
9-10. Each simulation and the cable from that simulation will be coded so asto be easily identifiable. This reduces the chances of a simulation being initiatedat the wrong time or out of sequence.
9-11. The actual firing of a simulation can be done by using BERFS or bycompleting the electrical circuit through direct contact between the demolitioncable and the power source; or by connecting both the demolition cable and thepower source to a control unit and completing the electrical circuit when required.
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When the demolition cable system is used, there is usually a requirement for extrapower sources such as blasting machines so that the demolition cables can bechanged without interrupting the continuity of initiation.
9-12. A control unit such as a ripple board (Fig 9-3) is invaluable when firingmultiple simulations. Each ripple board contact shall be coded to coincide withthe coded simulation cable connected to it. The firer merely has to complete thecircuit of the appropriate simulation to initiate it.
9-13. Firing Party. There shall be sufficient personnel to execute thefollowing duties:
a. Party Commander. Coordinate and direct the firing of all simulations.
b. Fire Controller(s). Initiate the simulation when directed.
c. Confirmation Party. At least two personnel are required to count andrecord all simulations which are fired, as well as confirm any misfires.The use of the Battle Simulation Planning Sheet is an easy way to keeptrack of all simulations fired.
RIPPLE BOARDS
9-14. A small rippleboard consists of nails driveninto a board. Firing circuitsare connected to each set ofnails and the power source isconnected to each nail asrequired. When connectingcircuits to ripple boards, caremust be taken to avoid shortcircuits. The bottom of theboard must be checked toensure that no nails protrudethrough the bottom (whichmay short circuit if placed ona conductive surface). Fig 9-3 Examples of ripple boardsGENERAL GUIDE FOR SET-UP
9-15. There are many methods of creating battle simulations. The methodwhich is most effective is the one that creates the most realistic simulation withoutcompromising safety. Often situations dictate that the planner apply flexibilityand initiative when attempting to achieve this objective. No method shall be
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considered unacceptable unless it contradicts safety procedures, or is likely tocause injury or undesired damage.
9-16. In all battle simulations, a safe work area shall be established on site forthe preparation of the simulations.
9.-17. Safety Fuze Lengths. When safety fuze is used in conjunction withelectric igniters and non-electric detonators for battle simulation, Fig 9-4 can beused to determine the safety fuze lengths.
Ser Battle simulation Safety fuze length(a) (b) (c)1 Single or first lengths minimum 50 mm2 Intervals between shots in a burst
a. C7/C8 Rifle 2 mmb. C9 Light Machine Gun 2 mmc. C6 General Purpose Machine Gun 4 mmd. 0.50 calibre Heavy Machine Gun 6 mm
3 Intervals between bursts 10 mm4 Intervals between rounds in a mortar or
artillery barrage10 mm
5 Interval between barrages 20-30 mmFig 9-4 Safety Fuze Lengths
MINIMUM DISTANCE BETWEEN SIMULATIONS
9-18. The minimum distances between explosives and accessories on thesame simulation relays are detailed in Fig 9-5.
Ser Explosives or accessories Distances(a) (b) (c)1 Detonators 100 mm
2 Detonators with 100 mm of detonating cord attached 200 mm3 Detonators with 200 mm of detonating cord attached 300 mm4 Explosive charges up to 1.0 kg 10 m
Fig 9-5 Minimum distances between battle simulations
SECTION/HEAVY MACHINE GUN FIRE
9-19. Single Shots. These are the most basic of battle simulation and can bedone in one of two ways:
a. a single electric detonator (with or without detonating cord attacheddepending on the simulation being represented); or
b. a single igniter electric with safety fuze and a non-electric detonator.
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9-20. Small Arms Fire. Simulations representing small arms or section firecan be set up using the electrical circuit for single or multiple shots (burst)initiation. Usually the simulation is made up of four bursts of three rounds. Thecircuit is formed by hooking up the leg wires of the igniters electric in a circularseries pattern as in Fig 9-6. The resources required for a C7/C9 rifle are:
a. twelve non-electric detonators;
b. twelve igniters electric;
c. first burst - 50, 52, 54 mm safety fuze;
d. second burst - 64, 66, 68 mm safety fuze;
e. third burst - 78, 80, 82 mm safety fuze;
f. fourth burst - 92, 94, 96 mm safety fuze; and
g. twelve 100 mm pieces of detonating cord.
9-21. Preparation. Small arms and heavy machine gun simulation isprepared as follows:
a. lay the demolition cable;
b. cut all safety fuze and mark the length with masking tape;
c. cut all detonating cord;
d. test all igniters electric;
e. crimp the safety fuze to the igniters electric;
f. crimp a non-electric detonator to the safety fuze, place it, then connectthe detonating cord. Repeat for the remaining items and lay thesimulation out as per Fig 9-6; and
g. begin hooking the leg wires to leg wires, until the circuit is complete.
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Fig 9-6 Small arms circuit layout
MORTAR AND ARTILLERY FIRE
9-22. Simulations representing mortar or artillery fire can be set up using theelectrical circuits for single or multiple shot initiation; the single shot circuitrepresenting spotting rounds and the multiple shot circuit representing barrages(Fig 9-7). The individual rounds are made up of basic charges using the amountof explosives which is appropriate to the simulation being represented. Usuallythe number of rounds in a multiple circuit is six, equal to the number of mortars ina mortar section or guns in a battery. If there is a requirement for a linear barrageinstead of a concentrated barrage, the simulation circuit is laid out in a straightline in the direction desired (Fig 9-1-8).
9-23. Requirements
a. six igniters electric;
b. six non-electric detonators;
c. safety fuze - 50, 60, 70, 80, 90, 100 mm length;
d. six pieces of detonating cord, each approximately 2 m length; and
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e. simulation charges:
(1) mortar/light artillery fire - six Detaprimers or six 0.125 kg plasticexplosive, and
(2) heavy artillery fire - six 0.5 kg plastic explosives.
9-24. Preparation.
a. lay the demolition cable;
b. test all igniters electric;
c. cut all safety fuze, and mark with tape;
d. prepare and place all charges as in Fig 9-7;
e. crimp the safety fuze to the igniters electric, crimp the non-electricdetonators to the safety fuze, and place in a safe area;
f. begin hooking the leg wires in one direction, (3 m pieces of connectingwire are required to achieve the 10 m spacing); and
g. tape the detonating cord leads to the non-electric detonators (Fig 9-7).
Fig 9-7 Mortar and artillery fire circuit layout
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Fig 9-8 Linear barrage circuit layout
ANTI-ARMOUR FIRE
9-25. Moving Vehicle. A simulation can be set up to create the illusion thata serviceable tank or vehicle has been hit by anti-armour fire. Dig a pit 2 m long,1.5 m wide and 1 m deep, and place the container in the bottom. Thoroughly mixfive litres of oil with five litres of diesel in a long cylindrical container cut in half(approximately 1 to 1.5 m long by 0.15 m wide). Pour five litres of gas on thesurface of this mixture. The amounts of oil and gas can be varied depending onhow much flash or smoke is wanted. Make a double thumb knot in a length ofdetonating cord and hang it so the knot is 20 to 30 mm above the gas. If thisheight is not correct, the fumes from the gas may not ignite and the simulationmay fail. The simulation is initiated electrically as the vehicle moves toward itfrom the opposite side to the viewers.
9-26. Warning. The change shall be initiated while the vehicle is still at asafe distance.
9-27. Stationary Vehicle. To simulate a tank or vehicle taking a direct hit byan anti-armour weapon, almost simultaneous explosions are initiated to show theinitial hit followed by the inside of the vehicle blowing up. The procedure is:
a. place a 0.5 kg basic charge against a non-serviceable tank or vehicle atthe exact location where the round is intended to impact. To enhancethe effect, have a slight stand-off between the vehicle and the basiccharge by placing a piece of board between them;
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b. inside the vehicle, behind the location of the basic charge place, orsuspend a five litre container;
c. in the bottom of the container, place a 0.125 kg basic charge with adetonating cord lead hanging outside the container. Pour two litres ofoil and two litres of gas into the container; and
d. both basic charges are initiated on the same electrical circuit usingigniters electric, safety fuze and non-electric detonators. The safetyfuze on the initiation set for the interior charge is 6 mm longer to allowfor a short delay between charges.
EXPLODING MINE
9-28. To simulate what happens to a vehicle when it runs over an antitankmine, the procedure for a stationery vehicle is basically followed. The onlydifferences are that the exterior basic charge is 1.0 kg and it is dug under a frontwheel or the front part of a track. The interior charge is still placed behind it,however, there must be sufficient metal between the two charges to shield it fromthe blast of the exterior charge. Initiation is the same.
SMOKE
9-29. Smoke is often desired to cover specific areas or to add realism to battlesimulation. The types of smoke dischargers employed by the Canadian Forces aremanufactured to be initiated manually, therefore it is necessary to improviseremote initiation.
Fig 9-9 Smoke pot No 24 MK 2
9-30. Smoke Pot, No 24 Mk 2. This smoke pot generates white smoke for15 minutes. To initiate manually, remove the cap and tear off the seal; then light
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the primed disc with a match fusee. To initiate remotely, use one of the followingmethods:
Fig 9-10 Railway fusee
a. using a railway fusee , pre-cut a small piece of board so that the fuseeand two igniters electric can be taped onto it directly opposite eachother and in direct contact with each other. The two igniters electric areplaced side by side and initiated at the same time. This initiation set istaped inverted so the railway fusee has good contact with the smoke potprimed disc; and
b. cut two pieces of safety fuze approximately 100 mm long. Bare thepowder core of each along one side for approximately 50 mm. Aftercrimping them into an igniter electric, place them side by side acrossthe centre of the primed disc. Apply sufficient pressure to splay them,ensuring that there is good contact between the black powder core andthe primed disc. Secure and waterproof this initiation set as much aspossible.
9-31. Smoke Pot, No 24 HCI. Generates white smoke for 15 minutes. Toinitiate manually, remove the cap, pull-out and unravel the igniter cord and light.To initiate remotely, crimp an igniter electric directly onto the smoke pot ignitercord ensuring that both black powder cores have good contact and are wellsecured to each other.
9-32. Smoke Pot, Type AP/3/F and AP/5/F. These generate white smokefor three and five minutes respectively in accordance with their designations. Toinitiate either manually, apply a lit match fusee to the sealed initiation point. Toinitiate remotely, the same methods that are used to initiate the smoke pot, No 24Mk2, can be used. Because of their smaller size, these smoke pots are much moredifficult to work with and the caution warnings must be observed.
9-33. When using smoke, a respirator must be worn by troops in the vicinityof the discharger.
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9-34. Grenade, Hand,Smoke, HC, C1 Series.Generates white smoke for oneminute. Manufacturedspecifically to be thrown byhand or be projected from arifle. Remote initiation isimprovised by securing thehandle to the body using tape,string or very light wire, securea detonator or piece ofdetonating cord between thegrenade body and the handle,then position the grenade so thehandle can fly off, and lastlyremove the safety pin.
Fig 9-11 Grenade, hand, smoke, HC, C1 Series
SIMPLE SMALL NUCLEAR SIMULATOR
9-35. A small, simple nuclear simulator can be improvised to produce afireball 10 m in diameter to a height of 30 m. The following explosives andaccessories are required:
a. five blocks (2.8 kg) of C4 explosive;
b. four pieces of detonating cord, each 2 m long, one piece 4 m long and a4 m ring main;
c. 20 litres diesel, 20 litres gas and 5 litres of oil;
d. one electric detonator; and
e. five Detaprime boosters (if available, but not essential).
9-36. It is prepared in the following manner:
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Fig 9-12 Simple small nuclear simulator
a. lay the demolition cable;
b. dig a hole, 1 m square and 1 m deep;
c. prepare five basic charges (with or without Detaprime boosters), one ofwhich has a 4 m double detonating cord lead. Place the charge with thedouble lead in the bottom of the hole and the remaining charges aroundit as per Fig 9-12;
d. insert minimum five garbage bags into the hole and fill with fuel (at lastpossible moment);
e. test the electric detonator;
f. connect the detonator to the demolition cable and tape it to the cradleon the ring main.
NAPALM SIMULATION
9-37. A very simple and effective method of preparing a small napalmsimulation can be done with minimum materials and labour in a very short time.The following resources are required:
a. six to eight empty, 5 litre cans;
b. 20 litres of gas; and
c. 50 m detonating cord.
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9-38. Preparation.
Fig 9-13 Napalm layout
a. place six to eight 5 litre cans in a row at 5 m spacing in the directionthat the flash is intended to travel. These containers can be placed onthe surface of the ground or dug in;
b. pour gasoline into each container, the level of the first being 5 cm andevery container afterwards having 2.5 cm more than the previous one;
c. suspend a length of detonating cord above and clear of all thecontainers in a row. It must begin before the first container and endbeyond the last;
d. attach a detonating cord lead with a thumb knot in the end to the trunkline leading into each container. The thumb knots must be positionedso they are 1.25 cm above the gasoline; and
e. initiate the trunk line from the end where the container with the leastamount of gasoline is located.
9-39. The size of this simulation can be increased by using larger containersand increasing the amount of gasoline. The distances between the containers canalso be slightly increased, but the height of the knots above the gasoline mustremain the same. If more sound effect is desired, a charge of appropriate size canbe hooked into the trunk line, however it should be positioned well away from thesimulation so that its shock wave does not interfere with the momentum of thefireball from the simulation.
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